Online travel isn't just for the geeky or the over privileged anymore. Most of the general sites have features like user profiling, map makers, and city guides, and do quite well at sniffing out low fares.

Vacations Gate - Your Gateway to Vacation Destination Information!
www.vactionsgate.com

12 Degrees (book travel itineraries for exotic locales)
www.12degrees.com/

Advanced Travel Service (great source for European train travel)
bahn.hafas.de/bin/query.exe/en

Air Traffic Control System Command Center (FAA-sponsored site listing US airport conditions, weather delays, etc)
www.fly.faa.gov/flyfaa/usmap.jsp

AirCharter
www.aircharter.com/

Allmusic (just what it says)
www.allmusic.com/

American Airlines (mostly of use to AA's frequent flyers)
www.aa.com/

Around the World in 80 Clicks (visit exotic places without leaving your PC)
www.traveladventures.org/

Arthur Frommer's Budget Travel Online (tremendous source of travel information)
www.frommers.com/

Avantgo (plan your trip with plenty of online guidebooks to work with)
www.avantgo.com/

Bed and Breakfasts (info on B&B's across the globe)
www.bedandbreakfast.com/

Bestfares (helpful, lots of discounts, though a hefty fee is charged to become a member and get full access)
www.bestfares.com/

CDC Travelers' Health (U.S. travelers can find out what shots they need for overseas travel, along with health bulletins and more)
www.cdc.gov/travel/

Cheap Tickets (good discounts but a long registration form)
www.cheaptickets.com/

Citysearch (information on just about every urban area in the U.S.)
www.citysearch.com/

Concierge (well-done interactive informational site)
www.concierge.com/

CyberCaptive (lists almost 5000 Internet cafes worldwide)
www.cybercaptive.com/

DigitalCity (like Citysearch, but a bit more hip)
www.digitalcity.com/

Discount Airport Parking (book cheap parking at U.S. airports in advance)
www.discountairportparking.net/

Faremax
www.faremax.com

Fielding's Dangerfinder (find out if that remote getaway spot is currently in revolution, infested with wild maneating animals, or what have you)
www.fieldingtravel.com/df/dplaces.htm

Flight Arrivals (find out when that flight is coming in; works in the USA and Canada only)
www.flightarrivals.com/

Flyer Talk (forum-based flight site)
www.flyertalk.com/

Fodors (online presence of the guidebook company, very useful for trip planning and with plenty of links to affiliates like Expedia and CultureFinder)
www.fodors.com/

Foreign Languages for Travelers (learn some useful phrases)
travlang.com/languages/

Frommer's (good travel guide and cost cutter site)
www.frommers.com/

Global Freeloaders (stay with locals in foreign countries for free)
www.globalfreeloaders.com/

GORP (lots of travel ideas for outdoor enthusiasts)
www.gorp.com/

Historic Hotels of America (lots of info on both their history and their current accessibility)
www.historichotels.org/index.htm

Hotel Discounts
www.hoteldiscounts.com/

Hotwire (online travel booking; little flexibility but good prices, and fast)
www.hotwire.com/

I Go U Go (large travel site, with reader-submitted travel diaries among the plethora of info)
www.igougo.com/

iExplore (good site for those looking into safaris, rafting trips, and other adventure travel)
www.iexplore.com/

If You Ski (info on ski resorts in the US and Europe)
www.ifyouski.com/

Journeywoman (travel side with the feminine touch)
journeywoman.com/

Lonely Planet Online (a travel site that provides "guidebooks" to the more rugged areas you might want to visit)
www.lonelyplanet.com/

Lowestfare (good place for last-minute buys)
www.lowestfare.com/

Manhattan Address Locator
www.manhattanaddress.com/

Menus.com (searchable listing of restaurants, including their menus, by city, zip code, restaurant name, or type of cuisine)
www.menus.com/

metroPlanet (train schedules and info around the globe)
www.metropla.net/index.htm

MSN Expedia (excellent all-around site)
www.expedia.com/

My Travel Rights (what your rights are as a traveler, from various countries' rules to your ability to reclaim lost luggage and damages for air crashes)
mytravelrights.com/

National Park Service (info on American national parks)
www.nps.gov/parks.html

One Day Hikes (info on day hikes in locations around the globe)
www.onedayhikes.com/

OneTravel.com (good all-around travel site; be sure to click on "Rules of the Air" for info on different airlines' baggage rules)
www.onetravel.com/

Orbitz (compendium of online travel sites, focusing on air travel)
www.orbitz.com/

OuterQuest (adventure travel site)
www.outerquest.com/

Outsidemag.com (has a section devoted to outdoor travel)
www.outsidemag.com/

Passenger Rights (delineates your rights as an airline passenger and compiles user stories of good/bad airline treatment)
www.passengerrights.com/

PluggedInns (a resource for finding hotels that have in-room high-speed Internet access)
www.pluggedinns.com/

Preview Travel (now part of Travelocity)
www.previewtravel.com/

Priceline (somewhat tedious, but a proven moneysaver)
www.priceline.com/

Qixo (discount airfare site)
www.qixo.com/

Quikbook (excellent hotel discount site)
www.quikbook.com/

Recreation (government site that gives vacation planning info on US national parks, etc)
www.recreation.gov/

Road Trip USA (11 cross-country routes including highway and attraction information)
www.roadtripusa.com/

Roadfood (where to eat on your way)
www.roadfood.com/

Roadside America (compendium of American roadside landmarks and oddities)
www.roadsideamerica.com/

Roomsaver (coupons for cheap hotel stays in the US)
www.roomsaver.com/

Rough Guide Travel (global online travel advice and info site)
www.roughguides.com/

SideStep (fair airfare comparison site)
www.sidestep.com

Site59 (good place for last-minute travel options as well as local recommendations)
www.site59.com/

Smarter Living (sign up for weekly e-mails offering travel discounts)
www.smarterliving.com/

TakeYourPet (lots of info on petlovers who want to take their animals with them on holiday)
www.takeyourpet.com/index.html

Theme Park Insider (attractions and hotel reviews)
www.themeparkinsider.com/

Time Out (Web site of the popular British travel publications, featuring information on over 30 cities and destinations worldwide)
www.timeout.com/

Trails (find hiking, riding, biking trails anywhere in the U.S.)
trails.com/

Transportation and Security Administration (planning on flying into, out of, or around the US? check here first)
www.tsa.gov/public/index.jsp

Travel and Live Abroad (U.S. government site giving info on traveling abroad -- global hotspots, immunization info, etc)
www.state.gov/travel/

Travelzoo (good last-minute airline prices)
www.travelzoo.com/

Travisa (apply for travel visas online)
www.travisa.com/

Trip Advisor (find out about the city you plan to visit)
www.tripadvisor.com/

Travel and Leisure (good site to research travel destinations)
www.travelandleisure.com/

Travel Channel (the Travel Channel's online presence; good destination info)
www.travelchannel.com/

Travel Chums (good source for local guides and info)
www.travelchums.com/

Travelbyus (good travel booking site)
www.travelbyus.com

Travelocity (not as easy or quick as some others, but very comprehensive)
www.travelocity.com

Travelscape (quite useful)
www.travelscape.com/

Trip.com (now part of CheapTickets)
www.trip.com/

Vacation Coach (go here for vacation ideas and recommendations)
www.vacationcoach.com/

W Hotels (good site for W customers)
www.whotels.com/

WebFlyer (plenty of info about frequent flyer programs)
www.webflyer.com/

Whale-Watching Web (listings of whale-watching tour operators are here)
www.physics.helsinki.fi/whale/

WhereEverYouGo (site that tells you what shops and services are in a particular locale)
www.weyg.com/

Worldisround (forum-based site sharing travel photography with commentary)
www.worldisround.com/

Yahoo Maps (fast becoming the best mapping site out there)
maps.yahoo.com/

Yahoo Travel (simple and fast, not a lot of frills)
travel.yahoo.com/

ZoloTrips (good resources for travel packages)
www.zolotrips.com/