which cpu

[Lemur]

roughly speaking there is a price/performance parity between AMD and Intel right now when talking about:

AMD PII X3 vs Intel C2D (100 - 130 GBP)
AMD PII X4 vs Intel C2Q (140 - 180 GBP)

It used to be that quality intel boards cost more than quality AMD boards, but they are both in the same 100-125 GBP ball-park these days.

Where this doesn't apply is the <100 GBP market as AMD A64 dual-cores are not competitive and the >200 GBP market where AMD does not compete at all.
As a general rule of thumb I would never spend more than 66% the price of the intended graphics card for the CPU, so if you are buying a 1GB nVidia 280GTX GPU for £270 then i would not spend more than £180 on a CPU which would mean either a Phenom II X4 3.0GHz or a C2Q 9400 at 2.66GHz to create a well balanced system.

Um, if you want to get into the nitty-gritty you might as well do your own reading. Here's Anandtech. Whacker likes HardOCP. Do a little digging around those two sites and you'll get a good idea of which CPU is for you.

[Furunculus]

i am into the nitty gritty, i build gaming PC's for me and my mates.

been a member of those sites since 2002'ish.

[naut]

If I were you TuffStuff I'd have a look on IBuyPower first, which is where those NewEgg rigs are from anyway. Since you can swap out anything you don't like, etc.

[ICantSpellDawg]

I figure that price is more important, so i'd like to have a rig that they set up and put on clearance. The prices on Neweg for cyber/ibuy are lower than the site itself.