I don't have any that I am extremely loyal to, but I will tell you to stay away from Orbitz. We tried to book a flight through them a few months ago, and right when we booked online, we got taken to a page that told us that the fare had just gone up about $25. At first, we thought it was just bad luck and timing, but then we double checked and saw that they were still advertising the price we had originally booked.
When we called to see about getting a refund of the additional $25, we were told that airlines change their rates all the time, and the higher rate was the correct rate. Even though we told them the price had not been updated on their website yet, we kept getting the same excuse. They refused to refund us the $25, so we told them to cancel our flight instead. We thought it was funny that they refused to refund the $25, but would rather lose us as customers instead.