I would personally suggest Sheffield. There might not be loads of choice for jobs, but you should find some casual work/temping quite easily. Housing is fairly cheap, a few hotspots apart. There are some really nice places to live - Crookes, Hunters Bar, Walkley Hillsborough. But it is not a place that you'd love at first sight - it grows on you. There is a great nightlife, though and it is really close to the Peak District... The mountineerers' capital of England.
I've got to say I would be an advocate of Sheffield too. I went to Uni there and then stayed up there working for a year, which would probably have been longer if it wasn't for family circumstances that forced me home.
I love Sheffield, I think it is a fantastic place that is throwing off its reputation as a grim, smog/factory filled industrial city. Lots of money has been spent renovating the City centre, it is right next to the beautiful Peak District, you can jump on a train and be in London in two hours, but you can also get up to the Lake District in a couple of hours too. Being a huge student city it is pretty cheap, and there are loads of bars/clubs/cafes/restaurants and plenty of green areas too.