Maybe Dragon Age II, criticized for its repeating dungeon structure, could have benefitted from something like this nifty dungeon randomizing web application. Not that I'm any better at it myself. I suffered the same criticism the only time my D&D friends, all older than me, let me DM an original dungeon. "Is there a secret door in every room?"
Chastened, I went back to being a half-elf barbarian-cleric and sulked my way through healing everyone in Dragons of Flame. If only I'd had Dave's Mapper.
Dave's Mapper is a multi-source geomorphing web application that launched about a month ago. It draws from 12 different sources of tiles to completely randomize dungeon maps. Tiles are swappable, and three sources are available for constructing a city map. The dungeons can be capped or left open to suit other purposes.
There is a ton of additional functionality for you to explore. Now I have to figure out where I'm going to put the kobolds and ochre jelly.
Dave's Mapper [site]