Type travel into Google, and you get 172,000,000 results. Here are T+L's annual picks of the sites you should bookmark now.

Five on-line travel agencies—Cendant, Expedia, Hotels.com, Orbitz, and Travelocity—now control nearly half of the Web-based travel industry in the United States, and the proliferation of Internet travel bookings is outpacing the growth of the industry overall. With so many sites to choose from, though, which ones will best prepare you for your next trip?We've highlighted the top links for each category from airlines to weather.

AIRLINES Seats, airport lounges, airline services, and flights are all rated by visitors to www.airlinequality.com, a site created by international aviation consultants Skytrax, who also run Flatseats.com, the definitive guide to first and business class on more than 60 airlines.

AIRPORTS Click on any of the 56 worldwide airports on Airwise.com to get the latest terminal news, plus shop and restaurant directories and ground transportation options.

AUCTION SITE On Luxurylink.com you can bid on resort stays and packaged luxury vacations at discounted rates.

BLOG Virtualtourist.com has an astounding number of posts from 400,000 members in 200 countries, on subjects ranging from diving in Oman to bird-watching in Mauritania.

CRUISES Cruisesonly.com has photos, tours, and last-minute deals on 124 ships; try Cruisecritic.com for very candid reviews from die-hard cruisers.

CURRENCY Xe.com's universal currency converter calculates foreign exchange rates for 184 currencies.

DIALING CODES Find international dialing codes, search a worldwide database of country and city codes, or reverse-search an international number on Kropla.com.

ECO-TRAVEL A carefully vetted collection of trips, activities, and 170 tour operators that benefit the environment and local communities can be found at www.responsibletravel.com.

ELECTRIC Kropla.com will also help you figure out which electrical system your destination uses and which plugs to pack.

FOOD Chowhound.com is rolling out sections on specific countries for its international posts. However, you still need patience to filter through the endless messages by foodies.

HEALTH CLUBS Find 5,600 gyms around the world (maps and driving directions included) at Healthclubs.com.

HEALTH SITE The travel section of the Centers for Disease Control's www.cdc.gov/travel has been revamped. In addition to giving health updates by regions, it now organizes advisories into four levels of importance.

INSURANCE COMPARISON Insuremytrip.com provides quotes from its 14 travel insurance partners in an easy-to-read format.

INTERNET ACCESS www.geektools.com/geektels is a searchable database of more than 4,300 hotels worldwide that have wireless and wired high-speed Internet access.

LANGUAGE At times laughably literal, Altavista's Babel Fish translation site, world.altavista.com, is helpful in a pinch. Translate a block of 150 words between 37 language pairs.

LAST-MINUTE SITE Smarterliving.com will e-mail you airfare deals once a week. TravelZoo.com's weekly top 20 deals can be either last minute or advance sale; either way, they sell out fast.

LOYALTY PROGRAMS Webflyer.com will manage your mileage programs and keep you abreast of the latest air, hotel, and car-rental programs. It also has a mileage tool to help you consolidate points.

MAPS Search by address, business, or airport name at Mapquest.com. You can also get point-to-point driving directions.

PET Petswelcome.com is a searchable database of 25,000 pet-friendly hotels, B&B's, ski resorts, and beaches. It also lists international vaccination requirements and quarantine policies.

RATINGS It costs $26 per year to access ConsumerReports.org's reviews of airline seats, hotel beds, rental cars, and more, but there's no better place to get the unbiased lowdown. The recent redesign makes it easy to access four years' worth of archives.

SPAS Spafinder.com is still the most comprehensive spa site in cyberspace. But for those seeking spas in New York City, San Francisco, and Los Angeles, Splendora.com's beauty page has more specific treatment categories.

TIME ZONES Find out what time it is anywhere in the world and create your own clock of up to 16 cities at Timeanddate.com.

TOURISM Over a thousand domestic and international convention and visitors' bureaus and tourist offices are at your fingertips at theTourism Offices Worldwide Directory, TOWD.com.

TRAINS Following its relaunch earlier this year, Amtrak.com makes it easy to book on-line. Find links to other U.S. trains at UStraintravel.com.

WEATHER Search international weather forecasts at AccuWeather.com, which will also help you plan activities like stargazing, sailing, and skiing based on weather conditions.

The next generation of "meta" travel agents—search engines that scan on-line consolidators, suppliers, and the major booking sites—have now added international booking sites and low-fare carriers to their repertoires. Three of our favorites:

Kayak.com Still being tested at press time, Kayak will search 35 sites and allow you to sort airfare results by departure or arrival time.

Mobissimo.com scours 55 U.S. and international sources and converts foreign currencies to U.S. dollars.

Qixo.com mines info from agencies, major carriers, small charter companies, and discount airlines—28 in all.

The most heavily used booking sites—Expedia, Orbitz, and Travelocity—have few exclusives with their vendors, who are trying to drive more customer traffic to their own sites. This year, our tests revealed a decrease in price differences among the major bookers, and, in many cases, better deals on the individual sites of airlines, hotels, and car-rental agencies. But the on-line travel agents continue to grow, because of what they do well: vacation packages—bundled airline tickets, hotel rooms, and car rentals that you put together yourself—and increasingly flexible search tools. Here's the latest news:

Price Test $202 for a round-trip flight from JFK to LAX Oct. 8-17; $339 a night at the W Los Angeles Westwood
Best New Feature Its package section has a calculator, so you can figure out how much more you'd be spending if you bought all the components separately
Flexible Searches Only for most popular domestic flights. But there's a flexible hotel search option and a calendar showing the range of prices for specific dates
Car Rentals Following Travelocity's lead, Expedia has rolled out "total pricing" (i.e., the price includes taxes and fees)

Price Test $202 for a round-trip flight from JFK to LAX Oct. 8-17; $284 a night at the W Los Angeles Westwood
Best New Feature Following a redesign, the site now lets you search for your return flight first, but will still show you round-trip fares to help you keep the price low
Flexible Searches For weekend trips (all weekends in a given month), flexible stays (by number of days), and bonus days (up to three days on either side of your chosen dates)
Car Rentals Orbitz, too, offers "total pricing." The site searches 22 car-rental companies worldwide; Travelocity and Expedia offer 11 each

Price Test $203 for a round-trip flight from JFK to LAX Oct. 8-17; $288 a night at the W Los Angeles Westwood
Best New Feature When booking a cruise and flight together, you can choose from the site's regular flight options rather than having to buy a pre-selected flight
Flexible Searches For both domestic and international flights, by the lowest prices first, but you must click through multiple windows to see all your options
Car Rentals The first of the three to introduce "total pricing." Search for a rental location by address, zip code, or local attraction