Sigil Prep, the only D&D setting where you can play a Drow cheerleader.
Out of all of those, my absolute favorite type of dungeon has to be the ruins of a lost civilization. Caves are nice and arcane sanctums are too, but caves tend to be too on theme and sanctums get too random and weird. Ruins have the largest range of believable options of fauna available while not making players' brains hurt too bad (normally). Want dragons? Check. Want a beholder who set up shop in an old watchtower? Check. Tribe of Kobolds? Check. Giant slime mold? Check. There can be all kinds of traps. Treasure tends to pile up in old storerooms, and ancient arcane knowledge tend to lurk in musty libraries. Plus you can always mold and rust and disintegrate anything too powerful for the players.
Plus, I love architecture. We can get soaring cathedrals, squamous geometry of an ancient race, or, my personal favorite, everything sized for non-medium characters. My absolute favorite dungeon I've ever made was a giant statue of a giant that was a tomb of a giant in the middle of a jungle. The stairs were chest height, meaning that it took them forever to get up a flight of stairs when large wall crawling creatures where chasing them. Doors were a pain in the ass, because the thief had to stand on someone's shoulders while picking a lock, and normal thieves' tools did jack squat on giant locks. Even better, most of the loot was too big for them! It was awesome.
Plus, ruins have their own beauty.
My love of ruins may be why I love Monte Cook's new Numenera setting so much. The entire world is built on the ruins of not one, not two, but eight past civilizations, and the world's technology is just scavenged from past civilizations. Dungeons exist aplenty. It's beautiful. Of course the sci fi leanings of that world also tickle my fancy, because I love mixing my sci fi with my fantasy (which is why I love Eberron). My current world has tons of ruins too, and I can't wait to run my players through them.