Having bought a new graphics card (XFX Radeon HD 5670; 16 x 9.9 x 32cm), I overlooked that my existing case is too small to accommodate it! My motherboard is an ASRock N68C-S UCC.
I can't justify spending more than £50; I am considering the Antec Three Hundred. Are there any cheaper options? I'm not bothered about sound dampening, I don't need room for crazy cooling, I don't need a PSU and I would prefer it not to look like a Christmas tree. Cable management is preferred but not essential; my existing case is from an eMachines 6260 which is pretty basic. As long as it doesn't rattle itself apart and isn't serrated, it's good!