For me... Eye candy is quite important also... but I am not a graphic freak like the foreigner, play PC Games on 8XAA and 8XFSAA and 8XAF .... nearly no "tooth" mark on the graphic... but for those kind of graphic you really need a good graphic card = MONEY of course.

I owning a PS2 and a average PC with 15" monitor.
For PS2, I really enjoy playing FF10 now, though its 6 years old but I just got my PS2 recently... I like the story, but sometimes I really felt I want to see the PC version, because I cant see the detail very good.

For PC, I playing NFS:MW, the weather changing, the framerate is very good, I saw the NFS:MW in PS2 before, seems to me is a different thing, your car looks slower, the weather not so real....

I dont have a XBOX then, but seems to me XBOX is like a PC, so the graphic wont be different so much. This is my conclusion :

If that particular console or system have a GOOD GAME, which is native to that system, so just go get it, although that graphic may looks bad, cause the main thing is the gameplay.

If you want to play something like car racing, FPS, you really need something good in graphic, its really make the game different.

I think most of the people would agree.