I know SanDisk class 6 has transfer rate of 20MB/s and their class 10 is 30MB/s but Transcend class 10 is 20MB/s... so personally I would rather go for SanDisk... I just got my 8GB SanDisk class 6 for $40 over the weekend... now my 60D can do video... the class 4 that comes with the cam does not even allow video recording past 8seconds...
Mine stupid Class 4 too. I didn't knew it made such huge difference till I got my 60D. Somemore I got 2x Class 4 8GB in my package...