I don't have anything very profound to offer, but if you haven't seen the printed compilations of Dyson's Delves you should put them on your shopping list.
The main attraction of his work is the precise yet cartoonish style of his maps, which reminds me of the excellent maps in Chaosium's early 80's Runequest boxed sets and adventures.
But the books are more than a map collection; roughly half of each volume consists of a map (or two or ten related maps) keyed with monsters, traps, treasures, etc.
The 'stocking' varies in approach and sophistication; most I would say have a charming simplicity that might remind you of the sorts of dungeons some of us 40+ year olds were writing when we were 15. They are a bit like small scale versions of the OSR megadungeons that are quite popular these days. Most are suitable for one night's play; a few are multi-leveled affairs you might explore for 3-4 sessions.
The last half of each volume presents maps with an evocative name and a matching sheet of blank ruled paper where you are encouraged to make your own stocking notes. I've already begun one ('The Cinder Throne').
A couple of the early maps are a bit blurry in their printed reproductions, I suspect because the original was small and the scan not sufficiently high resolution for scaling up. But overall they are quite beautiful and immersive.
The second volume contains a variety of outdoor locations as well as dungeons. I was hoping to see some of the city maps he's posted online, but perhaps those are intended for a future volume!
Arguably the best use of these is for pick-up games where you want a 10-50 room space on short notice. Or, as 'drop in' dungeons to put the flesh on the bones of your sandbox campaign.
I'll second that; I got I and II in print and am quite happy with them. He puts the unkeyed maps online (http://rpgcharacters.wordpress.com/maps/), so you can check them out for style or just use one for free. But its fun to have a printed book with your own keyed dungeons in it.
Great maps, solid write-ups and a life-saver for the time-harried DM.
Next D&D game I'm seeding my hexmap with these puppies.
Love the petrified-purple-worm-turned-dwarven-settlement.
Another vote to check out Dyson Logos and those wonderful maps if you don't already.
The maps and accompanying plot hooks are sure to inspire a GM.
Don't forget to check out his npc write-ups. Before he put up maps his blog was all about npcs for all the systems he found interesting. You get gems in there like his hate/train wreck obsession with deadEarth.