Sorry, busy weekend! I'll preface this with "this is my personal view" as a lot does come down to personal preferences, and some people have had bad experiences with all whichever brand you choose to mention.
I'd avoid Sony, and Apple if budget is tight.
Probably look at Acer, HP, Dell, Lenovo, Toshiba - definitely stick with the "known" brands rather than the likes of Packard Bell (dixons/pcworld own brand).
Would suggest looking for one with an Intel Core-i3 processor, 3 or 4 Gb memory, Windows 7 Home Premium Edition.
It probably won't come with Microsoft Office loaded (or if it does it will just be a trial version that only lasts a few days), so either budget about £80 for the student version, or use LibreOffice which is free.
I suspect that price will be about £350 for something decent, but I've not looked at prices for a month or so. Actually have just had a look and prices have risen so you're now looking at £380. It really is worth considering waiting until after christmas if budget is tight, as prices are *very* likely to drop by about £50 in the sales.
If that's a lot more than you were considering, might be a good idea to say what your budget is, and I could maybe have a look to see what the best deal might be in your budget.