Well, I'm the type where you'd have to pay me to take a game system. The game systems themselves are cheap, but the games are way overpriced unless you buy used. That's why I like PC gaming. Cheaper games and more versatile hardware. Plus, I don't even own a TV to hook a game system up to anyway, except I could use my PC (I have composite/S-video inputs).
Edit: But that Nokia N-Gage looks pretty neat. I saw one at Electronics Boutique yesterday on a display that was being set up. Looks pretty nice, but I'd wonder how well it works as a phone. And the $300 price tag is a bit steep, except it does play MP3s, have an FM radio, and have a lot of other neat features. I paid $200 for my Nokia 6610 so I guess the extra $100 for a mobile gaming system isn't too bad. And the game selection looks promising.