good info again chaps - thank you all

Your help has directed me along these lines:
As I said before, basically I'm after a new mobo/cpu combo for use with win7 and hackintosh'd with osx. This means gigabyte mobo for osx compatibility. I've drawn up the following three specs:
The cheap option
Gigabyte GA-EP45-UD3LR
2*Crucial 4GB (2X2GB) DDR2 800MHz/PC2-6400 Ballistix Memory
Intel Core 2 Quad Q6700 2.66GHz
Arctic Cooling Freezer 7 Pro Socket 775 Processor Cooler
£297.86
Top core2 option
Same as above with Q9550 2.83GHz
£343.05
i7 Option
Gigabyte GA-EX58-UD3R
Intel Core i7 920
Corsair 6GB (3x2GB) DDR3 1600MHz XMS3 Triple Channel i7 Memory Kit
Scythe Mugen 2
£466.03
Given these three options, from Less than three hundred quid, to just over four hundred and fifty, bearing in mind that it is going to be used for lightroom in windows7 and apple aperture in osx, would you gentlemen say there is much to be gained from the more expensive options? Am I gonna notice the difference? I daresay the machine will not be upgraded during its lifespan - likely replaced wholesale - that is indeed what I am doing here....as before, any and all thoughts much appreciated
