I also tend to use orbitz to find the cheapest fare and then book with the airlines. Orbitz, expedia, kayak, they're all about the same as far as I'm concerned.

And for hotels I'm mostly using hotwire at the moment, in combination with betterbidding which has so far had 100% accuracy in predicting which hotel I'm going to get... or at least correctly predicted that I'm going to get one of two equally palatable alternatives (Airport Sheraton vs Airport Hilton? Who cares?)