Just thought I'd butt in add my 2cents.
Sheffield is a decent choice. Like Elle said it's really cheap to live in, and student nightlife is great as it caters for loads of students (Hallam+UoS = Bajillions of students!!!), and UoS has one of the best Unions in the UK. The University itself, is pretty decent, and part of the Russell Group.
Bad points - Well, it's extremely hilly, great for running not so when your going on a night out. The law library could be improved a bit, as many of the texts are lacking in numbers. There is the main library - MASSIVE, which is open 24hrs during exam time.
If your doing law, then expect roughly 400 odd students to be in your year. Yes, there are a lot of them!!! Therefore the core subjects such as Public Law, Contract and ILLS will be based in the Octagon, which is basically a massive audotorium. So depending on where you live, expect to be walking, if you choose Halls of Residence, then Tapton is the recommended one, 5 mins from the law library, about 10mins from the Octagon.
The gym is really good, and they usually have special offers for students.
Apart from that, what can I say?