That is still a very reasonable spec (although 2gb RAM is now a little low for gaming). I wouldn't bother replacing it for now, performance between Intel Core 2 Quads are very close to the Intel Core i7 in games- while going to AMD would just be a side step.
Intel are planning on bringing out a new generation of chips at the end of this year/ beginning of next. They will be based upon new processor sockets, so buying now would limit your upgrade paths. I am still using an old Intel Core 2 QX9650 and plan to hold out until at least then.