You can't go wrong with either SanDisk or Lexar for CF cards (I own several of both brands). Having said that if you can afford to I'd highly recommend investing in the fastest cards you can (preferably the Lexar 1000x... and it looks like B&H has a pair of Lexar 1000x 16GB cards on sale currently for under $150) as you'll appreciate their ability to quickly clear the camera's buffer.
yeah that's what i was thinking regarding the buffer.
presumably a fast card is required for video, is that right?
i'm in england so the B&H sale won't help me unfortunately.
shooting in raw how many shots 'roughly speaking' would i fit on a 16GB. Maybe 2x16GB is preferable to a 32GB?
depends on what your shooting! For weddings I generally go with mRAW ---a 16 GB card can do about 800 or so at mRAW...closer to 500 if you go full sizred RAW, and closer to 1000 if you go sRAW (depends on what your shooting too, more texture, colors, detail in the shot leads to larger file size).
I tend to prefer Sandisk, with lexar being my second choice. I have borrowed kingston cards at times and gotten errors (had to reformat the cards, they worked after that but having to reformat doesn't give me confidence!!!)