http://www.vayama.com/
a very nice web 2.0 mashup. feels a lot better than any other of the international travel database interfaces. nice use of google maps, ajax 'did you mean' for airport selection etc.
better stil is destination selection via click on the map!
it's almost as much fun searching for your flight than the flight later on will be.
recommended.
not too surprising backed by one of the biggest dutch travel logistics companies. flying dutchmen ....