Since the 80's handhelds have existed as a pretty powerful gaming platform. The first major one being the Gameboy and then it's various redsigns we're now at the Vita/3DS. That being said, our current handhelds don't particularly resemble the Gameboy, as many designs have been cycled through since its original release. 

In terms of design alone, what is your personal favorite handheld?

Mine is a tie between the GBA and GBA SP actually, both designs just feel perfect to me XD I like the layout of the original GBA a lot and the buttons feel better than on the GBA SP. But the SP has a great clamshell design that I also really love

*Remember we aren't going by innovation here, just physical design itself. However if you want to add how it was innovative you can.

**Handhelds that predate the OG Gameboy can count as well

I absolutely love the Vita's design. My only complaint for it is the back touch screen which I wasn't a big fan of.

I absolutely love the New 3DS' design, but the slim Vita looks sick too.

This by far. Basically the closest thing we have to console quality analog sticks, and we have two of them(not like the N3DS's 'nub'). 4 face buttons, nice D-Pad, solid triggers. I love Vita.

From the three basic designs, of which 2 are reather similar, I like the "Game Gear" design best, followed by the Clamshell-Gameboy design and then the classic Gameboy.

Game boy and GBA are the only one I ever found comfortable holding for long periods of time. All the rest make me feel unfomfortable after an hour or so.

I like the design of Nintendo's handhelds, but I think the PS Vita has the best design.

GBA SP for being very portable and not making you look autistic while playing in public. For playing in my couch, Wii u off-tv is by far the best, not a portable though.

PS Vita