There are a number around, like WD, seagate, Toshiba, Maxtor. Might be worth looking in somewhere like PC World to see what they have in and what you like the look of.
Also worth looking on their web site before you purchase one as they have web deals and you can collect in store, I have done this once or twice and the price has been very close to the cheapest I could find it on the web, but I could go and get it there and then - they also do a price match, but don't seem to price match to Amazon anymore :bang: