I may be weird, but I can't remember being floored by any games at the time of their release, maybe because I didn't get around to playing a lot of the most graphically impressive games until long after they came out. The best looking SNES games (Chrono Trigger, Seiken Densetsu 3, Final Fantasy VI, Super Mario RPG, Super Metroid) I didn't get to play until long after they came out. Same with the best looking PS games (Chrono Cross, FFIX), and in fact I played FFVII so long after it came out that its graphics were no longer impressive to me. Even FFX I played a few years after it came out due to not having a PS2 at the time. Despite that, though, all the games I listed in parentheses did impress me graphically.
Oh. Yoshi's Island! That's a rare example of a gorgeous game that I played when it came out. I'm still amazed that they were able to pull those graphics off on the SNES. Wind Waker, too. I never got to finish it, but I did get to play several hours of it on a friend's GameCube and it was stunning.
Someone buy me Xenoblade so I can marvel at it thanks.