Hi Mate,
I normally recommend the Transcend 133x cards, they're the best value ones and I've never had any issues, just again be careful how you mix scsi.device and file system as some don't mix, with OS3.9 I just use SFS and keep 3.9's updated device, I find this works totally fine but with PFS3 can give issues unless you use Cosmos' version. (In my experience) If you ever need advice on this matter listen to Thomas at EAB, he knows he's stuff
I've also had sucess with Generic (the Chinese ones) Kingston and Sandisk cards.
I've bought a fair few CF from MyMemory:
http://www.ebay.co.uk/itm/Transcend...AsAccessories_MemoryCards&hash=item43c16f86af
They seem to be reliable.
Good luck,
Steve.