If you really want something that's reasonably priced and work well, I've used M-tec brakes before, they provide discs, you can either have them plain, drilled, grooved, drilled AND grooved or slotted. Plus you can get some pretty funky coatings as well in terms of a black or silver coating, to prevent rust.
I think it's around £125 delivered for a set of pads with a coating. Not bad really, worked well on my old 280mm setup.. arguably under a lot more stress than my 345s.