New PC / Motherboard Combo - any tips ?

[andys]

Looking to upgrade my spare (render slave PC) and i'm - as always confused as hell about all the new CPU options. Currently it has an older Q6600 chip at 2.4Ghz, so I want something much quicker.

My other main PC is an i7 920 - bought just after the i7 was introduced. It's quick - and the 4 cores (8 with hyperthreading) are great for my 3D rendering... but can I get similar rendering speed from a cheaper i5 these days or is the i7 still the way to go?

Anyone know which chip / board combo is best 'bang for the buck' at the moment - UK prices too please

Ta.