I have a T1i (ok, the wife does) and I've purchased MANY MANY "class 10" memory cards, but they all don't seem to perform very well. After a few snaps (50-100) they get unbelievably slow to the point you need to wait 10-30 seconds between pictures.
I've tried formatting them in the camera as many others have suggested. I've tried many different manufacturers and all the class 10 cards seem to be crap. I have a class 2 and class 4 generic, and it seems to work better overall, but is consistently semi-slow snap to snap at about 2-3 seconds per pic. I ran speed tests and the class 10 cards perform on par as do the class 2 and 4 cards for their rating. I've been buying 32gb cards lately and most of the cards we have that work ok are all 8gb. Maybe a 32gb is just too big?
What do you guys use size, speed and manufacturer wise and how reliable are they? Should I just get a box full of cheap 2gb cards and just change them out after 50-100 clicks?