To me, Wii (seriously)
Mario Galaxy's graphics are amazing! The sequel will probably be even better!
For the HD twins... hmm, from what I've seen so far, that Splinter Cell multiplayer thing trailer wins. It's so cool the animations of both players on the same screen, both looking like spiders climbing on the wall! Plus the messages and objectives on the scenery are amazing!
And I just can't understand how you all can be that excited with car graphics! They may be "perfect"... but I they don't get me excited or astonished... they just look boring.
Edit: Bayonetta is amazing too! Shockingly great graphics!
Mario and Sam Fischer will have to work realy hard to take the crown from her!