graphics that made you say "wow"

[Bodhesatva]

It's interesting to see how people are interpreting the original question differently.

A few took the question in its most obvious direction, which is "Games with photorealistic graphics." A few took it a step beyond that, and made it "Games with artistic style which impressed me, whether that be  photorealistic or otherwise," and an even smaller group took teh question as "technical feats or significant accomplishments in graphical evolution."

Half Life 2 on the Xbox, Wii Sports, and Shadow of the Colossus are clearly not cutting edge anymore and have been completely and utterly outstripped by modern games; they are, however, still important stalwarts of technological evolution, each in their own way.