Kayak

What it is: An encyclopedic search engine for hotels, airlines, cars, cruises, and vacation packages that scans not just direct suppliers, but also third party travel sites.

Booking fees: None, since it's not a booking site (which means no results are given preference). When a user finds a suitable trip, he/she is directed to purchase it directly from the site on which it is advertised.

Hidden fees: No cancellation fees from the website itself—you're just responsible for airline charges.

Customer service: Full disclosure with addresses and phone numbers on two coasts.

The final word: Our favorite! They have a comprehensive and unbiased database, and there's no agenda as to which search results populate first. Plus, it has great creative filters like "no prop planes" (if you don't want a puddle-jumper).