Hey thanks guys for the replies, I would never of known AMD for gaming! and the replies have, once again been brilliant!
I am going to go with the 3800 and the Video card is going to be a 6800 GS PCI-E, due to the fact my client doesnt really want to spend LOADS (He also wants a 19" monitor and 8.1 Surround). Of course this may change once I discuss it with him.
Thanks for all your replies it has been most helpful!
You're customers have been getting ripped....
In response to this, I should of made it clear that I have never really touched on specifying gaming systems. I build custom machines for programmers and developers, and in my experience Intel have always been a reliable performer in this field.