The DS, no contest. The sheer amount of great games of that system is only rivaled with the PS2. Plus, the DSLite model can play GBA games, which has some of my favourite games ever.

Best handheld ever made? It's definitely the Playstation Portable.

GBA SP is my most favorite ever.

The complete absence of any mention of the Sega Game Gear makes me sad. Not because I would call it my favourite handheld, but because it is at least as worthy of a mention as the Game&Watch, at the very least. But then, I'm pretty sure most members, here, don't really know much about pre-PS gaming.

My actual answer is 3DS. But then, I suspect that my favourite will be the newest of the ones I like, at any particular time.

I was between ds and 3ds but chose 3ds basically for the reasons mentioned in OP. The gameboy color deserves a special mention too though. You never forget your first....;____;

That one's kind of hard... if we're basing it on how much you liked it in its time as opposed to at this moment, then I really liked quite a few of them heh

My first handheld was actually the game gear, and I really really liked that one, though the battery life admittedly sucked.

The gameboy was cool but even back then I thought the screen was just unacceptably poor (especially when compared with the Game Gear). The Gameboy Color was a lot of fun as they actually managed to provide a color palette for games that didn't originally have one, and I got to experience Pokemon for the first time.

Largely skipped Gameboy Advanced... DS was fun, PSP was great... I guess I'd have to go with the 3DS XL just for the combined libraries of it and the DS, the larger size (very comfortable to hold), and impressive battery life while having a lot of great games.

Vita by far

I lent my 3ds to my gf 2 months back, she played it a couple of times but wants a Vita now. I haven't played the latest FE, I couldn't really get into awakening so i didn't really follow whats been going on with the latest one, or is it two? three? two FE and a dlc? xD i dunno.

I voted PSVita since most good PSP games also run on it, i was also a big fan of the original DS but I never really enjoyed the 3D in the 3DS and the Vita just felt much better in my hands and modern.

Overall I love handheld gaming so there is no wrong choice :)

I only had the psp.
And I really enjoyed owning that console.