Anything Class 6 or higher will work fine for video, and also allows you to hit the maximum frames-per-second when shooting bursts in Continuous Drive mode.
Anything faster than a Class 6 is overkill; it can improve the transfer-to-PC speed, but the camera won't get any faster.
I have a pair of Kingston 16G Class 6's, and they work just fine in my Rebel T2i....
Dreams Unlimited Travel is committed to providing you with the very best vacation planning experience possible. Our Vacation Planners are experts and will share their honest advice to help you have a magical vacation.