I recently built a new computer (Nov 11) and I have had some mixed feelings about the components I selected initially. It runs decent but I am a little unsatisfied with the case, gpu and cpu. I'm a fairly seasoned builder (Back to AM2/LGA775). The last rig I built before my current one was in 2008. Things have changed so much and I have a good handle on what is new but there are a lot of features I dont quite understand yet.
Is an upgrade seriously necessary? Honestly, your system is perfectly solid all around. Dont waste your money on it yet, wait a year or two when you notice slowdown and notice that you ened better parts.