It's easy to see why travelers booked over $2 billion worth of rooms online last year. They have immediate access to room inventory, detailed property specs, even photos. And many sites run specials on hotel rooms for last-minute travelers. - Christopher Elliott

PlacestoStay.com
Easy-to-search inventory of more than 17,000 hotels, inns and bed & breakfasts.Search by location, special deals or ativity, including skiing, golf and beaches. A query for golf hotels in California yielded a special at the Hyatt Regency Monterey with room rates "starting at $135"-a rate that turned out to be actually available, not just a teaser. But read the fine print, which the site includes for each property.

BedandBreakfast.com
For those who prefer intimate lodging. This site lists more than 27,000 small homes and inns worldwide, searchable by amenity, keyword or location. Offerings range from Pale Hall Country House in Wales to Piney Grove at Southall's Plantation in Williamsburg, VA.

Last Minute Travel
Book late (four weeks or less before your arrival date), and pay less. Selection is considerably smaller than some of the other sites-about 700 properties list their specials here-but the deals can be substantial.

QuikBook
Specializes in "distressed" inventory, or rooms that would otherwise go unsold. Rates at its network of 600 properties run from 20% to 60% off regular prices.

Small Luxury Hotels of the World
Not for the faint of wallet. But if you want luxe, click here. Search by country or resort type (e.g., spa, eco reserve, private island). Click on Fiji's Turtle Island, say, and you'll find copious information on rooms, dining, facilities and leisure activities (everything from fancy dress parties to mud fights). You can also check the local weather and consult a currency converter to figure how much all this will cost.

Travelscape
Discount outlet with abundant dirt-cheap specials. You'll find 1,900 hotels in more than 250 cities - and not just the bottom-feeders.

VacationSpot
Not just hotels. This site's 25,000-plus properties include inns, villas, cottages, bed & breakfasts, even chateaux. A pop-up calendar shows availability for many properties. Also features last-minute deals.