I think it's great that you've distinguished between "social" and "night" life. Durham has an EXCELLENT social scene, but its night life might not suit all. (I'm perfectly happy with it, but some people choose to go to Newcastle instead, which is apparently awesome and really cheap to get to.) I don't think reputation should be a deciding factor, really, if only because I really don't want to get back into one of those debates! Though Durham would definitely not lose that fight here. I think job prospects are good for any of those unis, so long as you get a good degree!
I don't know a lot about the other unis. Bath is a beautiful city but I can't imagine it being that exciting, my friend goes to Cardiff and loves it, and Manchester - no idea. Check out timesonline.co.uk in the Education in the Good University Guide to check out the subject tables to see how each one fares for the subjects you're planning to take.
Oh, and DEFINITELY visit - you'll only really be able to decide where's best for you if you have a look around. For example, I knew when I went to Warwick that it wasn't for me, even though I'd been keen on it beforehand.