mine is
www.expedia.it for a few simple reasons, they are FAST, they have the BEST rates and they have all the best combos for connecting flights and stuff like that, plus you can even choose your meal, first time happened to me last week, i was on the airplane and the hostess comes there "we have a special meal for you" and i was like "what the....." because when i created my expedia profile i chosen fruit meal but i did it by chance... so i was laughing and all the ppl were looking at me cuz i got the special meal.....PRICELESS!! ;-)
what's your favorite?