Honestly, you probably won't see much improvement with anything currently out. With Haswell coming out in June, I would wait till then. Even then, I am unsure how much of an improvement you would see. Your current chip is still plenty fast.
Thanks for the info, I was unaware that the 4th gen CPU's were on their way so soon! I suppose I'll have to have a talk with you about which motherboard I'll be needing when the time comes.