Hi there,
Do you already have a s1366 CPU?
Also, may I ask what you will be using the PC for?
In that case I would strongly suggest you wait until January 9th and pick up one of the new sandy bridge CPUs and motherboards.
Something like the i5 2500K and a P67 motherboard would be my choice.
In games, the new i5s (sandy bridge architecture) will be faster than the "old" i7s (nahalem architecture).
However, in most games performance will be bottlenecked by the graphics card, not the CPU (especially if its a quad core).
An i5 2500K will be ~£170 and the P67 boards will likely be starting at ~£100.