Platforms Worth Targetting for Portable Games?

rudescotsman asks: "Hi, I'm an independent game developer who just finished his first game on the Pocket PC and SmartPhone platforms. I targeted PPC/SP originally because that's what I owned and the dev tools are easily accessible, but now I'm thinking I'd like to write games for other platforms too. What platforms do Slashdot readers think are appropriate for a one-man game coding-squad to tackle?"

"Here are my beliefs:

PalmOS is doable, but in order to get any kind of graphics out of a Palm you need to target ARM-based Palm devices. How many Palm gamers actually have these more expensive Palms?

Tapwave Zodiac is tempting, their SDK is easy to license, but how many gamers are actually dropping the cash to buy these?

It doesn't look like it's too difficult to get into Nokia NGage development, but how many gamers are taking the NGage seriously?

Consoles and GBA are out of the question, these platforms are locked down so only the big studios can play, and I simply don't have the resources to make a title for these platforms that can stack up against the competition.

Since I'm a small fish in a big pond, I hope Slashdot readers can be my market research team."