The Antec 900 comes in at just over £80 but worth the money. It has excellent cooling and is well built.
Other than that, the Thermaltake V9 isn't too shabby at around £75.
A lot depends on what you want your case to look like, side window, how many drive bays, how much expansion room, PSU included or not, hot swap bays, neon lights blah blah blah......
Good luck with the build!