It used to be the GBA with glorious games such as Minish Cap and Pokemon ruby, but the 3ds took it's spot some time ago. I just couldn't resist Luigi's Mansion 2, Zelda: a link between worlds and Mario Kart 7...

The DS. It started off slow but it ended up with some of the best and most innovative games ever and the Lite model is one of the most aesthetically pleasing game systems ever.

Favorite games are Mario Kart DS, Picross, Picross 3D and NSMB.

The 3DS because it has Kid Icarus: Uprising (one of my favorite games overall) and it can play the huge DS library, the DS is second because of Pokemon platinum

Would say the DS but the 3DS is backwards compatible for DS and has a better then garbage online store with the eShop compared to the DSiWare.

I love more then a few GBA games and wish I could play them but 3DS has been a godsend.

Frankly it's been all down hill after the GBA making this an easy decision.