Upload & Sell: On
Prices have come way down in the last year. You'll want Class 10 for dealing with large images and HD video. I feel the best deal is a 16GB card, but 32GB is best if you are going on a longer trip or shoot a lot without card changes. I have a 32GB in my 60D.
I'm economical and my favorite brands are 1) Kingston, 2) Transcend 300X, and 3) Ridata. I've had good results buying cards on ebay (look at the feedback percent).