Any speed requirements or is a nominal 20mb (or even 10/5/2mb) enough?
We were with pipex (now talktalk, so cancelled immediately) and just signed up with plusnet, can't recommend them yet though, early days.
There is a broadband comparison site for business connections, although not gospel, gives you an idea.
Always heard good things about Eclipse - use them at home and have done for 5 years. Static IP's were free back then, so I got a range for home use! whoop.