Please, please don't pick a university based on appearance. You'll spend at least three years there studying, and it'll be on your CV for the rest of your working life, so you might want to consider factors like the course, ranking, optional modules, accommodation, the nearby city etc.
Though Durham is the nicest looking university I've seen in person. King's College, Cambridge also looks great, while Edinburgh seems quite picturesque and I've heard quite a bit about Nottingham (which looks quite nice based on a quick Google search).