which games this generation will be considered classics in the future?

[Rainbird]

Metal Gear Solid 4, Super Mario Galaxy, GTA4 (unfortunately) and BioShock would be obvious ones.
Valkyria Chronicles, LittleBigPlanet, Fallout 3, Burnout Paradise, Braid, Left 4 Dead, Call of Duty 4 and Gears of War are all games I think will be remembered, maybe not on the highest level of classics, but still up high.

For future releases, I think games like Killzone 2, Flower, Heavy Rain, Resident Evil 5, Street Fighter IV, MadWorld, Final Fantasy XIII (+ Versus), God of War III, Gran Turismo 5 and many more will be considered classics in some way.

EDIT: Doh, of course, Portal!