I'm a newbie here, but from reading around forums, your build looks good!
From what I think I know vaguely about, HD, RAM, Mobo, CPU, Heatsink, Case and GPU are all good choices (praises have been sung about all the models you chose. either that or they get recommended a lot). Some thinks you might want to consider (and might have come up earlier in the thread, sorry I haven't read everything):
CPU: If you can, buy Q6600 G0 stepping (as opposed to B3). Apparently they run cooler! Check out
this threat if you haven't already.
GPU: Again, apparently a good bangforbuck choice, with excellent eVGA service (+ step up programme). You might want to check if you are getting superclocked or not superclocked version. From what I understand, the superclocked is factory overclocked, but done very well, so for a computer idiot like me, well worth the extra few pounds. Just somethign for you to consider...
HD: have you considered 2HD, one for OS and one for everything else- a good idea for problems with reformat etc. You could of course partition your single HD, but thats not quite as good an option! Equally, an extra HD gives you a backup!