YES, without a doubt get at least 512meg. And even at 1280x1024 it matters. Take the Crysis demo for example. I am running an 8800gts with 320meg, and I can't turn everything on high and run with more than 2xAA because of video memory limitations. It wont even let me choose higher and even at those settings I get alot of memory hashing and swapping. (hense the random quick pausing in the game occasionally).
Another example is World in Conflict, I've only played the demo but with all settings on high with AA enabled 1280x1024 and you get alot of excessive hashing and it even tells you "Video memory overload"
This site gives some specs on how much memory is used with Crysis.http://www.incrysis.com/forums/viewtopic.php?id=11614