Fellow photographers ask me what CF cards I use with my Canon 7D. Since the Canon 7D has two digic IV processors, it can take advantage of the UDMA card speeds. UDMA cards can get expensive but I have found the SanDisk 16GB CF UDMA 60MB/sec to work great! I rarely fill up the buffer when shooting BIF and I shoot RAW too!
For the money, the SanDisk 16GB CF 60MB/sec card for $111.00/card on Amazon get the job done. I carry 3 of these cards in my photog vest.
Also Calumet, just released their new brand of 16GB UDMA cards which writes at 63MB/sec. They are $145.00/card.