Rogue Legacy is a roguelike platformer with plenty of very interesting mechanics. The way your new characters come to life when your old ones die, the exploration of the castle, the options you have to customize your characters, everything is almost flawless. I've found some issues here and there that I would maybe tweak a little for the way I like to play games but otherwise it's a blast.
Quadropus Rampage is a mix of roguelike and hack-and-slash systems with some deep customization options, upgrade paths, random loot and good replay value that ultimately is held down by some unwieldy controls and a few spots of confusion here and there.
Dungeons of Dredmor is a roguelike with a good sense of humor and tons of customization options to give you incentives to try again over and over. While I feel the items are overwhelming and the maps are too full with stuff, I think it's one of the best dungeon crawlers I've played.