^^^^
Well I would say even at Games too, when u have a Getter Dedicated cards like 8600+ u wont see any difference with 4GB

I have 4GB, for OverClocking purpose I poped 2 out out of the Box

, and relly no difference in 2GB or 4GB whats so ever
but yeah, one stuff really helps with 4GB thats Virtualization...

its damn easy to run 4/5 instance of Virtual OSes, on VPC or VMware