Thanks folks.

BTW, this isn't one of my usual games I recommend, but if you have a Wii, I can't recommend highly enough the game that came out this week for Wii Ware:

Cave Story

The only apprehension I have in recommending it is that I haven't played it on the Wii, and they've done a lot of work to get it on there. I played it for the PC, and it's one of the best 2D platform gaming experiences I've ever had.