I have a compact truvativ chainset I've used on my bikes. From what I found when needing to replace the BB is that the SRAM and Truvativ basic GXP BBs are the same, although often with a slightly different price, the cheaper usually out of stock! The other two options are the Hope with adapters mentioned above, or the SRAM Red Ceramic GXP BB, which is about the same price as the Hope ceramic. Just found there's now a Chris King ceramic GXP BB which is even pricier but Maximum Bling, although it may be difficult to seperate the Hope and the Chris King for reliability. The Chris King one will have their grease ports though, but is only available from the USA as far as I can see (The mtb and ropad versions are different).
So, its SRAM/Truvativ at around £25, Hope steel at £60, Hope Ceramic at £90, Sram red ceramic at £100, or Chris King at £90+intl shipping.