Be wary of expedia.com. I have just booked my flight through them (normally I go travelocity.ca, but expedia.ca was cheaper), and the price for my itinerary increased about $100 from one day to the next.
If I rebuilt my itinerary with the exact same flights on the exact same days, the price would always come back to the original price!
I will agree that expedia is generally cheaper than anywhere else I have booked from. It just try to takes suckers for a ride...
"Get it? Got it? Good..."
Always looking for the longest route with the most transfers.