Airlines:

American Airlines
Continental
Delta Airlines
United Airlines
Southwest Airlines
Northwest
USAir
Virgin-Atlantic

Cruises:

Cruise Vacation Center

Hotels:

Hilton Hotels
Sheraton Hotels
Radisson Hotels
Ramada Hotels
Crowne Plaza Resorts
Travelodge
HotelQuest

Other Travel Sites:

Biztravel Plan a trip, make Online reservations
Time Zone Converter Great tool for determining time in other time zones
Travel Resource Find any subway in the world, also info on currency, maps, weather...
Travelocity Maximum power for the do-it-yourself traveler
Conde Nast Traveler Travel advice and reviews
HotelQuest Provides lowest rates available on over 3,500 Hotels