With the even larger budget and your plans to overclock, you may well want a better motherboard, but I don't know much about them.
The CPU cooler, GPU and HDD could all probably be improved too.
CPU Cooler - ,
Thermalright HR-02 Macho (buy this from Scan if you don't get the case at Specialtech) or
be quiet! Dark Rock 2
Prime will be quietest but cool the least, Dark Rock 2 is still nigh-silent but cools better, while I think Macho would be the coolest, but louder at load.
GPU - I'd suggest the ASUS 670 (avoid the "TOP" version), it's the quietest of the third-party coolers and it cools better than reference, but the Palit one's so cheap it kind of makes all the third-party coolers look extortionate by comparison. Kikatek might have a Gigabyte one for £320 that's slightly cooler, but louder (still quieter than reference), but the site's down so I can't make sure.
HDD -
Better 1TB
Fast 2TB
Low-power 2TB
Keeping in mind, you probably don't have much use for "faster" in the HDD scheme of things considering you have an SSD, though if you think you might end up using the HDD for games as well as the SSD, avoid the Western Digital (or get the
256GB SSD if you think it's worth the extra £58).
Edit: Why the hell does linking to Amazon mess this forum up so badly?