With all the different styles of adventures out today, my favorite is still the classic dungeon crawl. It's tough to beat a straight delve into some kind of underground cave, ruined citadel, or abandoned wizard's tower.
|Time to go exploring!|
Dungeon crawls have a lot going for them. There's the exploration aspect, where the party is finding new places and filling out a previously-blank map, the loot aspect from plundering the dungeon, interaction/combat with NPCs or monsters, and world-building and other adventures from finding interesting items in the dungeon (a treasure map, an ancient scroll describing another adventure location, an evil artifact that can only be destroyed in a specific way, etc.). It's just very interesting to me in a way that most city or plot-heavy based adventures just aren't.
Plot-based adventures can be fun, especially if you've got a good DM that has several plots available to give the players a choice on which to follow up on, but nothing beats a good hack 'n slash dungeon crawl for me. “Go into the dungeon, slay some monsters, and grab some loot” is how D&D started, and 40 years later, it's still a damn fun way to play.
Note: In the original D&D 30 Day Challenge, Post Twenty-Eight was supposed to be about a character I'd never play again, but I don't really have characters I would never consider playing again. There are a few characters I've had that died, but most of those were one-shot PCs and none were really memorable. So, I changed the topic to something I feel is slightly more interesting.