That looks like a well rounded build
The Q9550 might be worth the extra £30. The 9450 is OEM isn't it.. so only 1 years warranty, not that it will matter really. If it's just gaming you might consider a dual core but quads do have benefits if you want other applications going on behind the scenes of games. Also the Q6600 does still represnt pretty good value in quad core world.
Definatly skip the Asus maximum, the DFI P45 is pretty awesome and probably what I would buy. The Asus has more features though, so I'd check the specs and see if there is anything particuarly special about the Asus for you.
The 620W corsair is on the super savers on today only, £78. It's an awesome PSU and personally I wouldn't like a coolermaster PSU though I'm sure they are perfectly accpetable.
Stick with the 640GB 16mb, I doubt the 32MB will be all that much different especially if it's just loading times in games etc..
And for the P182.. would you want any of the decal ones?
