I've got 1-4GB, 1-1GB in Extreme III, same in Ultra II and a 4GB Microdrive for backup. I don't like using the Microdrive that much because my battery life suffers, but now I've got 3 batteries for my 5D so I should be good! Going to RAW, and those 13 MB files eat up cards like a kid with candy! By the way, Ultra II and Extreme III cards are on sale at Amazon.com, very nice prices! 4GB Ultra II $72!!!
I use a Transcend 8GB 120X High Speed CF card (I'm very happy with it's performance btw) and it's on sale now on Amazon.com for only $95.99 and the 4GB version for ONLY $49.99!!!!
That is VERY CHEAP and a darn right STEAL!!!!
4GB at 120X under $50.00???? WOW!!!
Just ordered another 8 GB card for backup.