In the old days, you called your travel agent when you wanted to plan a trip. Today, you can do it yourself. Thanks to the Internet, you can book your entire vacation, from airfare to hotel accommodations, with just a few clicks on your computer keyboard.

Popular travel booking sites like Expedia, Travelocity and Priceline have turned every household into a virtual travel agency. They make it easy to instantly compare prices on airfare, lodging, and car rentals and then make your own reservations. Joining these big, well-known sites are a lot of newer, lesser-known travel booking sites, such as Bookingbuddy, Hotelicopter, AboutAnywhere and SideStep.

Planning your trip on one of these sites could potentially save you money-- up to 50 percent or more. But with so many different travel booking sites available, how do you know which ones offer the best deals, and which ones are just a waste of your time?

Although travel booking sites offer different services and prices, the definition of a "good deal" ultimately depends on what you want. If you're looking for a five-star hotel at two-star prices and you're not picky about which part of town you'll be staying in, then a name-your-own-price site will probably work well for you. On the other hand, if you want more control over where you stay, then you might prefer a Web site that lets you pick hotels and flights before comparing prices.

In this article, you'll see some of the most popular travel booking sites, and you'll learn how to find the ones that will give you the most bang for your travel buck.