Airfare search sites - what's your favorite?

What sites do you use to search for airfares? If it works well in SE Asia, bonus points :-).

Kayak.com I think works in the Americas, but it doesn't find good fares in SE Asia.

Dohop.com is an interesting one - a bit patchy on SE Asian fares.

I've been using Protected content as it's good for SE Asia, and I like the "search whole month" features, that gives a graph of recently found fares for the month - helps in choosing a good day to travel.

Any other tips? I wouldn't mind having another site to compare results.