Sure, you can go online to one of the biggies like Orbitz, Expedia and Travelocity for hotel, rental car and air fare. But there's a whole new collection of Web sites for savvy travelers. Some are aggregators, following the successful model of Kayak.com, which pulls data from a variety of sources so you can compare airfares. Others combine social networking and consumer reviews, such as VibeAgent.com. Some are improved versions of old favorites, like OrbitzTLC Traveler Update, which allows travelers to share information about conditions at more than 40 airports in the U.S.

Here is a guide to some of the new or reincarnated sites, with one important caveat: Some of these sites do not yet offer the comprehensive database of reviews and information available on older sites like TripAdvisor. So don't be surprised to find minimal listings and reviews for some destinations, especially obscure ones, as you explore what's new in the next generation of travel Web sites.

boo.com (no connection to the defunct fashion Web site): Offers travel reviews from consumers, search capabilities for 2,500 destinations in 170 countries, comparison hotel prices, and booking through boo or hotel Web sites. Includes restaurants, bars and other interesting things to do in chosen destinations.

vayama.com: An online booking agency for international air travel with flight and fare options to about 190 countries. Allows travelers to enter preferences for connecting airports and travel time. Also has information about obtaining visas, passports and immunizations.

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VibeAgent.com: Combines user-generated reviews, meta-search capabilities, and social networking (think TripAdvisor plus Kayak plus Facebook) for personalized hotel recommendations and booking at the best prices. Personalizes hotel searches via three categories: "Ambience," "Activities," and "Recommended For," such as a romantic hotel near the beach for gays and lesbians. Users can create custom groups, or become members of existing groups, such as marathon travelers, to exchange stories, tips and recommendations. Connects you to the Web site with the best price for booking from among 120,000 hotels.

YELLOWPAGES.travel: Searches up to 12 travel Web sites, including Orbitz, Kayak, Expedia and SideStep. Users click on each site's logo at the top of the page for the results. SearchBoth.com, a subsidiary of YELLOWPAGES.travel, allows users to search two travel sites at the same time and places the results from the sites on a split screen.

ProfessionalTravelGuide.com: Offers reviews of hotels and restaurants from professionals - journalists and expert reviewers from the travel industry - including insider tips and specific, detailed information about more than 159,000 hotels. These reviews are more like what you would find in a guidebook than in an anecdotal consumer review. Also has a customized guide for users who are traveling to several cities.

yapta.com: Stands for Your Amazing Personal Travel Assistant. Enables travelers to tag flights from several airlines, including American, United, Delta and Continental, and alerts them when the fare drops. But unlike farecast.com, which predicts whether prices are rising or dropping, yapta can continue tracking prices even after you purchase the ticket. If you booked directly with the airline and the price drops below what you paid, you may be eligible for a refund or credit from the airline. Other rules may apply - for example, some airlines charge a re-booking fee to capture the travel credit, so check the details. (Yapta currently only tracks airfare prices for U.S.-based carriers, though it does track international flights for these carriers, which include American, Continental, Delta, United and U.S. Airways.)

TripIt.com: Organizes travel plans into one master online itinerary. Forward flight, hotel, rental car, and other confirmations to an e-mail account, and TripIt will e-mail travelers with the link so they can see and manage the itinerary. Includes weather, maps and city guides. Users can customize the itinerary with additional information, such as directions to a restaurant or tourist attraction.

Orbitz.com: Offers a new social networking component — OrbitzTLC Traveler Update — with real-time updates from travelers about security wait times, traffic and parking, taxis, etc. at more than 40 airports. Travelers can post the information on the Web site or send a text message. Orbitz encourages people to send information by giving out perks to people who send in tips and updates, such as a free pair of airline tickets.

BestTripChoices.com: Matches travel personalities with best destinations. Travelers take a test and are classified into one of six travel personalities, ranging from "Venturers," people who are extreme risk takers, to "Authentics," people who want a relaxing, lazy vacation. The site recommends travel destinations based on the results. The destinations have been rated by travelers with similar personalities who have visited those places.