I used Alliance Travel this summer for trip to Ireland. Actually used their online site and found prices really competitive! What was really cool, too, was that when my flight was booked, I was able to download all my flight info into my Palm PDA through Alliance's relationship with their online booking service and Infotriever. Was constantly updated whenever I was online! In office staff have always been friendly and helpful, too, although I mostly use online.
Good prices; downloadable flight info to PDAs; helpful staff