I have a prejudice against using any card with an annual fee.
I used to feel this way and then I really read up on the travel hacking stuff. Now I keep a detailed spreadsheet of CC expenses (annual fees) and cash value of rewards redeemed. Last update: $1425 spent on annual fees, $8287.03 in redeemed rewards, which does NOT include any cashback cards (I wanted to show myself that it was better than regular cashback cards).
Net: $6862.03