Agree with Sqrl, that's a very solid machine. Unless you're using certain apps that actually take full advantage of another CPU's strengths, it's a pointlessly big $$$ jump to the next tier.
I've built 6 machines around the 955 BE & M4A78T. They're used in a gaming/design studio. Not your standard office paper-pushing workplace.
That board + CPU combo is easy and fun to OC. Try that instead.