Graphically, I think we're at the point of diminishing returns. After, say, the next generation of systems, it'll be hard to tell the difference between a screenshot and a picture.
In motion, however, will be a different story. The uncanny valley is a scary place--who knows how long it will take before a character's actions, words, feelings, etc. make us feel like we're in a living, breathing place?
Could I trouble you for some maple syrup to go with the plate of roffles you just served up?
Tag, courtesy of fkusumot: "Why do most of the PS3 fanboys have avatars that looks totally pissed?"
"Ok, girl's trapped in the elevator, and the power's off. I swear, if a zombie comes around the next corner..."