i think the revolution will be the best, but it probably wont keep up sale wise with the ps3. the other two will have better graphics, but thats about it. all the games will play the same, last as long and follow the same old routines. which is cool, but nintendo is going to offer so much more.
there is only so much good graphics can do for a game, it looks really good and makes things easier to play, but if its not a fun game its kind of pointless. games like ssbm dont have awe inspiring graphics, but its among the most entertaining of the fighter games. same with fire emblem on the cube, pretty standard graphics but a very very cool game.
im not saying that the revolution wont have awesome graphics compaired with the cube and ps2, and maybe even ps3, but it has so much more going for it that its not really worth worrying about if its 20% less capable of some of the visual things of the other consoles. the ps2 and x-box 360 seem like one trick ponys, they have awesome graphics, but i dont see the companys doing much else. they wont up the average game length or offer any new gaming experiences. just the same current generation stuff with a prettier picture.