Upgrade help

[Rhysjoe]

Need to upgrade my system but need some advice.
I currently have:

E6600@stock
P5N32Se Sli deluxe M/B
4Gb of Ocz ram
280 GTX

Was thinking of getting this:

Q9550,Asus P5Q Pro and another 4 gig of ram.

But would i be better off paying a bit extra and getting an i7 system.

 

[Rhysjoe]

I have about £550-£600 if needed.I use the computer mostly for gaming.I have an arctic freezer 7 cooler but don't know the first thing about overclocking.