i use travelocity.

I always use Hotwire and never have issues. :) I like it.

i use cheaptickets.com and then compare it with expedia/travelocity etc.

I completely avoid American Airlines, their planes are so fucking cramped and uncomfortable. JetBlue is my favorite airline not only for seats, but you get your own tv and a fair number of snacks

im with coffinberry, travelocity.

cheapoair.com

I personally use bookingbuddy.com
it combos with all the other travel websites so you search a bunch of different places at the same time~

kayak.com Searches a whole bunch of places and you can modify and filter the results in so many different ways.

I always booked through Expedia. Not sure if that makes me an idiot (based on the above comments), but then again all my flights have been international.

Me first! Me first! ^_^

Pretty much everyone has suggested all the sites I'd recommend. Though I suggest also going directly to the airline's page and comparing prices, once you find the flight(s) you'd like on those travel sites. I've gotten big discounts that way, surprisingly.