DSi. It does everything plus play Gameboy games. Great design aswell.

3DS has the catalogue going for it (plus VC).
It's a shame the original 3DS had such a badly placed Dpad.
At least that got solved in the next iterations of XL and 2DS.

DSi can only play DS games...
DS and DSlite can play GBA games.

It was the DS Lite that was the best release of any of Nintendo's handhelds. It was sleek, it was getting LOADS of games, had an incredible battery life, and sold at a higher rate than any Nintendo hardware product ever.

The DS library was phenomenal, the only thing then 3DS had over it were Monster Hunter the Zelda games, and Mario 3D World. Other than that, the DS had a vastly superior lineup to 3DS. There were new RPGs almost every month on the system, and these included several remakes of core Final Fantasy and core Dragon Quest games, not to mention an ACTUAL core Dragon Quest exclusive, which is quite something considering this is the 9th instalment in the franchise that began console RPGs. DS had its share of original Mario and Zelda games as well, it had the better 2D Mario game by far. Mario Kart is more up to date on 3DS, but the DS one definitely made a much larger splash, and holds better memories for the fans than Mario Kart 7 (in a similar way to Mario Kart 8, obviously being the best Mario Kart currently available, but a shadow in the memories of fans when compared to Mario Kart Wii, or even Mario Kart 64 and the original Mario Kart).

And saying "backwards compatibility is with the DS is why 3DS is better" is an incredibly weak argument. The backwards compatibility is there, but none of those games launched for that console, so it completely lacked the hype, the sales success, and the audience who actually played the game. The argument of DS launches are what make the 3DS better is invalid.

GBA, it was a great system, especially with the GBA SP, a lot of games came out on it fast, but the jump from GB was smaller and seemed almost purely cosmetic when compared to the jump from GBA to DS. The GBA ended up being a nice improvement from GBC, but DS was the true advancement in handheld gaming with the touchscreen included amo it's features.

The DS Lite, and the unrivalled library of games, including dozens upon dozens of RPGs, makes the DS platform irrefutably the best of Nintendo's handhelds.

Thats correct. I always forget which one does what. The Lite is the one im referring to. Great little system. I should charge it and see if it still works. Its been awhile now haha