Also, if you have former (or current) military family and are using USAA for anything (insurance, banking, etc.), they have a travel department whose main business is to book cruises.
I just booked my cruise on Glory (Dec. 31) through them, and it was wonderful. They guarantee the lowest prices online, and they mean it. They're not really "travel agents" so you don't pay them, but they are just as accomodating and helpful as if you did. My friends and I booked our cruise on Thursday with no hassle...it took 30 minutes and we were granted shipboard credits simply for booking with them.
The next day, after avidly researching our cabin, we realized that it was directly over the casino and 100% of the reviews said this was a -bad- idea. So I called back and was upgraded from a 4C to a 4E for practically no money at all, and the lady stayed on the phone with me for 45 minutes trying to help me find the best and quietest cabin still available. (Keep in mind that she also had to talk to the Carnival rep every time we considered a different room!) She was always as pleasant and helpful as could be, as was the guy I'd booked my cruise with the day before.
So anyone with USAA, I -highly- recommend using them for booking cruises!