You could, but then how are you supposed to use the controller? I think the vertical stand disqualifies it as a handheld. Maybe if you took the strap from some Oakley goggles and hooked it up to your face... *light bulb*
Speaking of handheld, I see no SEGA Nomad on the list. No love for the portable Genesis? A portable Genesis! How cool is that?
Eh...I voted for the GBC. It's the one I always kept in my backpack from seventh to eleventh grade.
if you can read this, get out while you still can.
GP32, hands down. It was the first real "multi-function" and open source handheld - played games, displayed pictures, played music and (small) video clips and was a damn fine flashlight to boot. (I'm being serious. The back front light on the thing was that bright.) Yes, the official games from Gamepark sucked, but the passionate and obsessive homebrew community made up for it. Sadly, it's successor, GP2X, was a colossal disappointment. It was hard to use, the games sucked, it was glitchy as hell, and they expected you to be halfay decent at command-line Linux. They have a few new things out,but I have yet to look at them.
Number two is definitely the original Game Boy. The graphics might have sucked, but the games were fun, and that's all that mattered. Besides, I was ten. I wasn't exactly "picky" when it cames to games.
Number three is the good ol' Wonderswan Color. My brother got one of these for Christmas a few years back. Sure it was all in Japanese, but it didn't matter. That system introduced us to the two-pronged awesome that is "One Piece: Battle Colosseum" (best "licensed" fighting game not tied to wrestling or Capcom ever) and "Magical Drop."
I survived the TNA tapings, July 2015.
Survivor of the GFW Amped Anthology. I watched it so you didn't have to.
The GBA for me because it had phenominal games, but played all the original Gameboy and Gameboy Color games as well, and they looked incredibly sharp, even in black and white. I haven't played much DS, but since you can't play the original Gameboy games on it, I have to give the GBA the nod.