Overall good choices. Cases are a personal thing, but consider the CoolerMaster HAF series. HAF-X and HAF 922/32 are all very good, as is the HAF 912/912+ at a lower pricepoint (though these may not be available in the UK, I am not sure).
As far as your hard drive, 3TB in a single drive is asking for trouble. I'd get two 1TB drives (Seagate or Western Digital) or a single WD Black drive (here's the link: http://www.amazon.co.uk/Caviar-Black-7200-Internal-Driv...) plus an SSD for your boot. That'd be more expensive but would be the best all-around solution. More mechanical storage is cheap, but such a large drive with all of your data... well, you just don't want to be in the situation where it fails and you've lost everything.