Kayak is very user friendly and you feel like you need go no further in your flight search. It looks for the flight and gives you the best price options it can find - period. No unnecessary bells and whistles, just practical price options.
Kayak.com
A few points about Kayak -
- registration opens up other options such as information about destinations worldwide, and fellow kayak-er reviews
- simple layout - straightforward - just plug in the flight dates and go
- includes neighboring airports in searches
- permits searches for points around the globe - quotes are in U.S. dollars