Better lighting effects in general, not just a select few games that get good reflection on water and such.
Less invisible walls. This may be less of a graphical thing and more of a computing thing but it's still something I want out of consoles. If it looks like I can go there, I should be able to go there.
My theme song: http://www.youtube.com/watch?v=SBjQ9tuuTJQ Most people think they are the odd one out but never truly are. I am that one who actually is. :D
They will certainly be significantly better. It'll probably be the difference between early 360 launch titles and the latest and greatest looking games this gen when the consoles launch, and then much better as time goes on. I think that's a safe bet.
I mean, Forza 4 in autovista looks near CG minus the jaggies so I imagine next gen games will be amazing. Imagine Forza 4 autovista models (no jaggies) in a huge, populated open world city in GTA. I think that's entirely possible.