Desktop Dungeons has been a well-loved roguelike on PC for quite some time, and now it's finally available for the iPad! Just the iPad, though. Sorry iPhone users.
Aside from being optimized for tablet touch screens (rendering the whole "desktop" thing somewhat moot in the process), this iPad release contains all the content from the PC version - including the new stuff from the Enhanced Edition. It's pretty much a direct port, but it also lets you carry over your save from one platform to the other with DesktopDungeons.net.
You can get your hands on the new tablet-friendly Desktop Dungeons right now for $9.99.