I've always liked the look of the GP2X and Wiz. Honestly they look more my sort of portable gaming platform than my iPod has ever been and I wished I could justify buying one as I suspect it would be fun to develop for than something like the iPhone -- and a lot cheaper.

Personally I don't think the iPod is much of a gaming machine. It's more a PDA/music player I think, as the touch screen interface plus the motion sensors only really suit certain types of games, and the ones that disappoint me the most as a player are the ones that follow traditional game ideas but expect you to use some lame touch-screen emulation of joystick and buttons. The problem is that since there is no physical feedback as to where your fingers are and what you are doing, you can spend almost as much time looking at your fingers to make sure they are hitting the right area than looking at the game.
The only things that are going for the iPod/iPhone (and probably the iPad as well) as a gaming platform is the online store and the popularity of the device (with a large potential customer base), giving people who normally make home brew games a chance to possibly (if lucky) make some money doing what they normally do just for the love of it -- at least a greater chance of making money than developing for any other portable device. I often wish Nintendo had gone that route with their handhelds.

Anyway it's not a total loss.

I have seen some interesting concepts on the device that I wish could be played on other systems. For example Wolfenstein RPG. It's basically a cross between Dungeon Master and Wolfenstein 3D. I love it, but hate the controls -- even though in that case at least you don't need to worry about making well timed moves to dodge bullets etc. as it's pretty much turn-based (sort of, just like Dungeon Master was). Would buy that if it came out on the Nintendo.