I'd avoid thermaltake like the plague. a Noctua would be a much better investment than any other part of the spec, hell get rid of the dvdrw and use the £20 you save towards the Noctua.
I'd say you're fine with that PSU for that spec, there's way too much hype about Corsair going on when they're all rebranded Seasonics. At one time OCZ made the best PSU's on the market, the 500w OCZ will be fine, or a nice Enermax. Anything that isn't bottom drawer generic crap will handle the rig fine.
Have a look at TTL's excellent £600 gaming rig guide here: http://www.overclock3d.net/reviews/s...00_gaming_pc/1
for ideas, I would definitely ditch the OCZ RAM though. Mushkins would be a much better investment.