Very interesting question. At one people many people thought that 5th gen games would not be seen as classics because 3d was so rough around the edges. Fact is, for many of us over the age of 20 this gen will not be remember liked 4th or 5th gen was. But someone born in say 2000, and was 7 years old when Super Mario Galaxy hit will definitly think of it as a class. COD4 wont be because activision has spammed it, same with Guitar Hero, people will remember the series as a whole, but no single game will bea classic.
Games that might-
Uncharted 2, SMG 1, Zelda SS, Gears of War, Wii Sports (much in the way duck hunt is, in 10 year people who were 5-10 will talk about it like how it was so cool back in the day), Mario Kart Wii, New Super Mario Bothers (DS, maybe Wii)
Now due to the fact that some many series have mulitple releases I think it waters it down, but I think as a general statement these series will be looked back upon by the gamers who played them with much nostalgia- Gears of War , Assassin's Creed, Call of Duty 4 and beyond, Mario Galaxy, Guitar Hero.
Overall I think Gen 7 will hold up better than 6, and if it not for 5 being loaded with so many classic RPGs more than 5 too, you also have to remember, gen 7 will be the longest gen ever. Its started with the 360 in 05, and the first 8th will be in 2012 (WiiU), with the 720 and PS4 being as late as 2013 and 14.
I honestly dont
End of 2009 Predictions (Set, January 1st 2009)
Wii- 72 million 3rd Year Peak, better slate of releases
360- 37 million Should trend down slightly after 3rd year peak
PS3- 29 million Sales should pick up next year, 3rd year peak and price cut
