Its more of a question of what do you require it for? If you are just going for it because of the price without considering what you are intending to use it for then you could be going the wrong way. What is the PC for. Home office / inet access. Games / or other intensive graphical work?
gaming really. games as WoW, FM09, Unreal Tournament, Leftfordead etcetc. An upgrade on the GFX Card is a must of course but just ideas on the general system. Saying that there is another system up if people have thoughts..