RPG, supplement, you name it.  It's almost a shame that they still don't make these things anymore, but I have heard that the prices are usually pretty high for a good looking boxed set.

In any case, the best bang for my buck has been:

The Planescape Boxed Set. Almost perfect on all fronts (save using the AD&D 2E system, alas). I remember when it came out, it was IIRC the first ever boxed set with a $30 price tag (up until then all boxed sets from TSR and the like aimed for $20-$25). But man, I could actually feel a glow when I lifted the lid off.  

There were three books: A rules-y background book with all sorts of detail, a big fat awesome GM screen (at least I think it was this product, it may have been a supplement), a few very evocative and totally not-to-scale fold-out maps (in a good way; it looks like they were drawn by the hand of a planar cartographer),

but I think the best part was the 32-page introductory book: Chock from start to finish with evocative art, this thing was the Hook. It was the thing that said, "I want to be a Githzerai Dustman Assassin... and get in a giant debate with a Sensate".

All in all, I played the hell out of that set, until the box binding cracked.  I ended up buying most of the other Planescape boxed sets and books (even got a few signed with original art by Tony DiTerlizzi), but that first boxed set was the real deal.  A ton of ideas, and enough push-force to get you into playing the game with your own ideas.

Dark Sun 1E is a close second, but it was a little dry compared to the Planescape boxed set (although I've actually played more DS than Planescape).

-Andy

Planescape Boxed set probably, though were I to sneak in more, the whole shebang of the three Planes of... boxed sets would be supreme, for me.

For old school dungeon-crawly goodness, Rappan Athuk is pretty keen.

The little black box Traveller.  Hands down.  All of ONE piece of art in the whole thing (no, I don't count the one on the back of the box).  I was in heaven for years.

Next up, 1st edition Gamma World.  Plain ol' dorky fun.

!i!

Holmes Basic.

Classic Traveller.  Hands down, twenny tons of fun in a...box about...here, this size or so.

Displacement tons!

Bleh, this is no fun. Scooped by Ian. I was even going to say "Hands down."

So... HANDS DOWN my SECONDmost favorite box would be... hmmm... oh, the agony... well, I got the most mileage out of CoC 1E, but the one I loved the most, because of the beautiful cover image, was Pendragon 1E.

What IS it with the "hands down" thing?

Quote from: Caesar Slaad...were I to sneak in more, the whole shebang of the three Planes of... boxed sets would be supreme, for me.

Really, all three?  

I thought Planes of Chaos was really inspired.  Planes of Order felt kinda rushed... I dunno, just not quite as solid and "giving you ideas for game sessions" as Chaos.  I've never read the Balance set, though. That's one of the 2-3 Planescape supplements I don't have yet.

For me it was the Twilight 2000 boxed set.  I got more useage and fun out of it than any other.  Trapped behind enemy lines, no hope for backup, you're on your own.

Planescape was great, but I think my all-time favorite boxed set (keeping in mind that I'm too young to have owned very many boxed sets) is Masque of the Red Death.

Hmmmmm - Traveller, Ringworld.... Ringworld, Traveller... Decisions!

-clash

That ginormous black box that D&D came in back in the early 90s.

It's not a fair competition, though.  The only other RPG boxed set I ever bought was 2e Forgotten Realms :deflated:

Quote from: fonkaygarry2e Forgotten Realms

Dark Sun, both editions. 2e wasn't very good in terms of actual RPG content, but it was a really cool boxed set because when you opened it up, you got a cloth map of the Tablelands. I still have mine. Planescape was cool too.

Actually, that's one of my two criteria for the quality of the boxed sets - the maps. I also liked the DM screens you got. The books were always neat, but it was really that first feeling, when you popped the lid off for the first time and piled all the books up and then unfolded those giant maps on the floor and peered over them before you'd read the setting book, imagining what everything was going to be.

Call of Cthulhu 3rd Edition for sheer playability along with cool fluff (the 1920's sourcebook and the map).

Planescape for look and usefulness.

Holmes Basic D&D for out of the box fun.