Before clicking this thread, when I saw it was down to two, I knew it'd be DS and 3DS.
And that's one hell of a tough decision. I'm terribly fond of both. Altogether, in the DS family, I've owned 9 devices (currently still have 6 of them - DS Lite, DSi XL, 3DS, 3DS XL, 2DS, N3DS XL). Honestly, I think I had more fun overall with the DS, but that's mainly because I've gotten really big into handheld gaming and probably became too critical. The 3DS is in every single way except one a vastly superior handheld. That one thing being that the DS had a larger original library, and many more unique concepts. But the 3DS's library is still superior overall, I think, and vastly larger overall, with eShop and DS backwards compatibility.
+3DS
-DS
SW-5120-1900-6153
