Meh. There are actually some things 2D can do that 3D can't, in my opinion. I'm thinking Puzzle games. We have a whole bunch of top-down games viewing a board of some sort, where you need to use strategy to win. Sure, there are the same games with 3d Objects and an Isometric view, but can you really make it full-3d? I think if someone really did try to make these puzzle games really full-3D, it would detract from the playing value somewhat.

2D is in no way dead. If you look at Gamehippo, you'll see that plenty of the games there are in 2D. If you say that 3D games have better graphics, then I suggest you look at Starscape. There are plenty of examples that 2D, if not still going strong, is far from dead.