I've started work on creating my first roguelike, and so far it's been great. It's such a relief not to have to worry about all the problems that come with graphics, and since everything is cell-based, it makes collision detection, LOS and all the other stuff so much easier. I can actually enjoy making games again.
The only drawback is that only people that like roguelikes will want to play it, but my games have never exactly been super-popular anyway. http://www.youtube.com/v/jSD85IlkBc0?version=3&hl=en_US&start=
It's still very early in development, but since I don't have to create the graphics every time I want to add a feature, it makes development incredibly fast.