GadgetKen

Expedia is good when I need to do a more complicated booking or when they have a nice package deal. For instance trying to do end-to-end ticketing through LAS on HA to Hawaii but staying over only one or two nights in LAS to make a connection. Am trying Hotels.com (owned by Expedia) that another poster mentioned for a trip to Bermuda next summer...they had a short-term deal on Expedia and Hotels.com for the Coco Reef for far less than any other website had.

Orbitz sometimes has good deals on hotels by themselves. Got a deal for Channel Inn during Cherry Blossom Festival time in DC this year...plus didn't have to pay in advance (a rarity these days). Also the automatic money back on flights that somebody else buys for less on Orbitz policy is nice...although I've never collected on it myself with some of the more odd itineraries I've traveled on.

Travelocity has some good tie-ins with Amex or AAA for discounts. Also once got a deal for USAirways with first class on a couple of the flights for less than all-coach on other websites.

All are very useful if you are doing an odd flight pairing with airlines that don't have code-shares with each other. Has been useful when connecting to regional Caribbean carriers such as Cayman Air, LIAT, etc.