I have far more non-D&D books than D&D books. I really only own about a dozen or so D&D books, all 5e compatible, which is on-par with how much Unisystem I own. I have a huge selection of FFG RPGs (mostly the WH40K lines and those damnable Star Wars lines) along with a complete set of WFRP 2e. I also have a lot of L5R (3rd and 4th editions) Shadowrun (multiple editions, but mostly 3e & 4e), and Savage Worlds stuff. I own two sets of Decipher's Star Trek line and a full set of the LUG Star Trek line too. Mutants & Masterminds 2e & 3e also have a strong showing and I still have a full set of Exalted 1e (only!) books. Then there are the assorted "orphans" of the collection that I pick up on a whim (like Zweihander, Corolis, Cold & Dark, Polaris, and more).

Quote from: RPGPundit;1023171So, outside of what you actually play, how many different game system books do you own?

Is your stuff all D&D/OSR related?

Do you just have a few non-D&D books?

If you have a big variety of them, do you use them?

Outside of actual play? Probably 3 game system books, because they use different game systems. None of them are related in any way.

Quote from: RPGPundit;1023171So, outside of what you actually play, how many different game system books do you own?

Quite a few

QuoteIs your stuff all D&D/OSR related?

Nope.

QuoteDo you just have a few non-D&D books?

Nope.

QuoteIf you have a big variety of them, do you use them?

Yep.

To give you an idea of what's in my library, and I've lost a lot of RPG books when moving from AK to WA, and regained some of them through buying used.

Mutant Chronicles 1st edition.
Mekton II.
Basic & Expert D&D. (Moldvay)
The Basic D&D compendium.
1st Edition AD&D.
2nd edition AD&D.
The collected original Traveller rulebooks reprint.
Pathfinder.
3rd Edition D&D.
4th Edition D&D.
Lots of Rifts.
The Robotech books that cover Macross, Southern Cross, Invid Invasion and The Sentinels.
And odds and ends like Fiend Folio, the original Dark Sun setting boxed set. (Quite happy with that find.)

I plan to pick up 5th edition D&D, but I'm not in a hurry. I also want to get the FFG reprints of the WEG Star Wars books, when they come out.
I'd like to get Shadowrun 1st edition and Earthdawn 1st edition, physical copies.

I don't play D&D, but mostly play TFT (nearly everything) & GURPS (mountains of GURPS books).

The only D&D books I have (or ever owned) are the three from the 0D&D whitebox. I tried to play it but couldn't make sense of it.
I read various Basic D&D and AD&D books belonging to friends and even ran some limited sessions for them when I was about 11 years old.
I have Gamma World. Thought it was nothing I would ever play, though I did steal its random mutant tables for wild random extraplanar summons results inspiration in GURPS a couple of times, just to be unlike anything I'd think up myself.
I got Star Frontiers at a thrift store, read as much as I could stand, found nothing I could use and gave it back.

I think the only TSR stuff I have that I like playing are the boardgames The Awful Green Things From Outer Space and Snits Revenge.

I have quite a few RPG books for various other games, all of which I have read at least partially, and some of which I've tried to play or intend to eventually try playing experimentally, or to refer to eventually to use some snippets for some other games. Mostly they end up getting me thinking "huh, that'd not occur to me, and I wouldn't do it that way, but it gives me ideas of things to do" or just "how would that play out in GURPS? would that be a fun exercise?"

Not very, but what I have is mostly complete

AD&D
Classic Traveller
WEG Star Wars
Shadowrun 1st to 3rd Edition (including novels)
Call of Cthulhu 1st to 6th edition (excluding 3rd party stuff mostly).
Star Frontiers

And a lot of d20 crap.

Not really varied anymore.

Runequest
Stormbringer
HarnMaster
Rolemaster
AD&D with some B/X, and some OSR stuff.
Warp World/Time Lords
Chivalry & Sorcery
Traveller

Frontier Space (both books) is on its way.

There's probably more, but it's still boxed up from when I moved in June.

I have been thinning my collection, but I still have quite a large collection, with quite some variety.

In print I have:

OD&D, AD&D, Holmes Basic, BX, BECM, D&D 3.5, EPT, Arcana Evolved, and some other stuff in there, plus a variety of supplements and modules
RuneQuest (1st ed, 2nd ed, 3rd ed) and lots of supplements and modules, Ring World, Elfquest,
Classic Traveller (1977), plus a bunch of supplements and adventures, Mongoose Traveller 1st ed
EPT, Swords & Glory, plus a modest (reduced) collection of supplements
Talislanta 1st ed through 3rd ed plus most of the supplements (plus 4th ed on my chopping block)
Burning Wheel Revised, Burning Wheel Gold, Burning Empires, Mouse Guard, Torchbearer
Dogs in the Vinyard, Sorceror, and a few more "indie/Forge" games
Thieves Guild and pretty much all the supplements
Gamma World
Universe, Star Patrol, Space Opera, By the Light of Other Suns, and a few more SF games
Gurps 3rd ed
Champions
Arduin Grimoire Volumes 1-3
I'm sure I'm missing some random things that are buried somewhere

In print magazines I have complete runs of Dungeon Magazine and Different Worlds and an almost complete run of White Dwarf up through #70 or so, and small collections of other magazines

In PDF I have a lot more:
All the Classic Traveller CD-ROMs, MegaTraveller, GURPS Traveller Ships
Pretty much all the D&D stuff I have in print
Most of the RuneQuest stuff
Dogs in the Vinyard, Torchbearer, and some other "indie/Forge" stuff
A variety of OSR stuff
Lots of D20 stuff (I divested myself of most of the hard copy, but still have lots of purchased PDFs)
Talislanta (it's all legitimately available for free)
Various miscellaneous stuff, I'm really not sure what all is hiding on my hard disk

I have ditched tons of stuff I decided I would never play or use.

These days my purchases are made with great care. They pretty much need to be something that supports my primary game interests (OD&D, Classic Traveller, RuneQuest, and Burning Wheel).

Frank

I had a lot more stuff until about 6 months ago. I gave away or sold my GURPS collection (except for Dungeon Fantasy). I gave away or sold almost all of my AD&D stuff. I gave away my S&W stuff. I have my Aces & Eights stuff. Gave away my HackMaster and Kalamar stuff. I am pretty much down to my Palladium Books games and AiME. I have the core 5E books strictly for AiME.

I decided to stop buying books for games I'm not going to play. My group likes Palladium. My daughters like Palladium. I like Palladium. I like GURPS a lot too but it's so hard to get players into it because there isn't an entry point. So Palladium it is.

So, outside of what you actually play, how many different game system books do you own?

Depends upon how far back you measure, because I have a few systems that I haven't used in years, but did at one time, and might again some day.   Have never played and probably won't, I'd say less than 15 books over less than 7 systems.  It is probably less than that, but I'm allowing for oddballs books stashed where I've forgotten them.

Is your stuff all D&D/OSR related?

My D&D systems tend to be more complete (though none are all the way there), and thus a greater number of books, but I have more variety and systems represented in the non-D&D stuff.  OSR is a fairly minor component, as the subject matter of huge swaths of OSR products doesn't appeal, even if the systems do.

Do you just have a few non-D&D books?

As above, numerically a small percentage, but representing several systems.

If you have a big variety of them, do you use them?

The only books on my shelf that I don't ever use, or even consider using, are my D&D 3E books (which I did use a lot, once), a stripped down version of Reign, and a few books from Riddle of Steel.  The latter two I find thought-provoking to read.  Maybe they count as used, given that.  Anything I don't use tends to get tossed.  I'm only hanging onto the D&D 3E books to give to a friend that is currently overseas.  When those go, the entire collection will fit on a 30 inch by 6 foot bookcase, with room left for considerable growth.  

My "gaming collection" has always included books that aren't about gaming, but that I find useful in gaming.  For example, I have a book on oared warships by a naval historian, that I find extremely helpful.  But I also enjoy reading it for its own sake.  I just picked up a Culver's herb book, which is not a terribly scintillating read, but should be useful for some things I have planned.  That one is, for me, a gaming book, even though it was written well before RPGs.

Like ChristopherKubasik, it's weighted heavily toward either the early years or after 2010. Only real exception is some Savage Worlds stuff from the late 2000s and Pendragon. Early stuff is D&D or Traveller. Rest is quite varied.

Quote from: estar;1023177I think I got some  stuff here and there.

My entire collection is probably a little smaller than estar's GURPS collection.  Mostly fantasy, about half of which is Classic D&D/OSR related.  I have a smaller number of Sci-Fi books, probably about 1/4 as many SF books as fantasy.  This is physical books only (I probably have 2 or 3 times as many pdfs as physical books), although the ratio of fantasy to SF is probably the same for my pdf collection).  No other genres or universal systems except for the old generic D6 cookbook from the 90s and Mini Six, and Dogs of War, a modern-ish BoL variant.

Non-D&D/OSR systems include mainly lighter systems I pick up because my interests lean that way and they were cheap enough that it didn't bother me too much at the time.  Heroes and Other Worlds (a TFT clone), Age of Shadow (a D100/BRP derivative), Dragon Warriors, AFF, Ancient Odysseys: Treasure Awaits, Barbarians of Lemuria, Dungeonslayers...DW is probably the crunchiest of the bunch.

I think all my sci-fi is OSR based, like X-plorers, SWN, Tales of the Space Princess (not strictly OSR, but in the spirit)...other than WEG Star Wars.

I have used most of them, but many only once or twice.

Quote from: RPGPundit;1023171So, outside of what you actually play, how many different game system books do you own?

Is your stuff all D&D/OSR related?

Do you just have a few non-D&D books?

If you have a big variety of them, do you use them?

If we count only dead tree editions, I own only several games that I can count on my fingers. A significant part of them are new wave OSR games, because my tastes run to old-school lately.
If we count the PDFs, too, I have thousands of books without exaggerating. D&D and related systems are a small minority among those.
And yes, I use the whole varied group, usually running games from PDFs, with D&D and related systems taking up less than 5% of my gaming time.

I have a vast amount of stuff - more than Estar's pic. Indeed I had some young folks joking I should clear out some of my RPG books from my store room/spare room and give them a place to stay in London...
Although I have lots of non-D&D material, in recent years the great bulk of my playing time, and all my GMing, has been D&D and variants, including OSR stuff like White Star & Mutant Future. Just looking at stuff I have on the go GMing currently, there's my big 5e Wilderlands campaign and side games of 4e D&D Nentir Vale and 2e AD&D Council of Wyrms - I bought & printed the pdf out, put in a Dragonlance ring binder - my son/solo player complains that the cover image of humans riding dragons is highly derogatory.

Crazy amount of stuff. Over 700 boardgames and RPGs (inc. modules, etc), plus all those S&T, The General, and Dragon magazines.

And a few thousand painted miniatures.

And way too much terrain (inc. Dwarven Forge, et al).

So, rather varied.

No D&D books.
Mostly Shadowrun, followed closely by Powered by the Apocalypse, and then just cores like Runequest, Pendragon, Unknown Armies, Eclipse Phase, Mutant: Year Zero, Fate of the Norns, Dogs in the Vineyard, etc.

These days I play Shadowrun and PbtA, but I've used all my books at least once in my gaming life.