Well black 2 and white 2 are for the reg ds.
Probably next gen will be 3ds. but I doubt that will come soon, maybe in like 2 years. But personally I don't really like the 3ds. When you try to play regular ds games on it. the graphics are worse. they become blurry,which sucks. I mean I have a friend who has one and would gladly lend to me to play one game, when the game I'm looking to play comes out. But if you want it to play say 1 or 2 3ds specific games, I wouldn't get one. I prefer my dsi. Had it for over 3 years now and still looks crisp, and works like new.