Caravel's DROD is my favorite game at the moment, and possibly could be for years to come. If you haven't played it or haven't heard of it, I really suggest that you try it. There are free versions available (Architect's Edition, DROD 3D or something like that, ...), but I suggest that you try and buy the commercial versions. Go to caravelgames.com. I say this not as an advertiser, but as a fan.