eBay Inc., the e-commerce service provider, is all set to acquire WHI Solutions (WHI), a provider of software and digital catalog solutions for autoparts distributors and retailers for over 39,000 North American vehicles.

The San Jose-based company said acquiring WHI would help them expand selection and access to enhanced structured data to improve parts selection and value for customers while enabling parts retailers, distributors, dealers, and manufacturers to reach more customers.

Terms of the deal, however, were not disclosed.

This article tries to find out the five best  long-standing online car retailers in the U.S. market, catering to thousands of online car buyers everyday.

1.       CarsDirect

CarsDirect.com has been rated the #1 site for buying new cars online by Forbes, Time, PC Magazine and PC World, among others.

The Web site is known for their low, no-haggle prices and has a huge collection of new and used cars for sale. They provide a 'vehicle specialist' to help you buy a new car online.

CarsDirect even finds a certified dealer network near you to find your desired vehicle and negotiate a low price.

2.       eBay

Founded in 1995, eBay now boasts more than 97 million active users globally (the number's only rising) and is the world's largest online marketplace. eBay connects a diverse and passionate community of individual buyers and sellers, as well as small businesses. The company started its motor venture in 2000. eBay Motors' large, multi-dimensional marketplace offers consumers a comprehensive and convenient shopping experience.

3.    Amazon Auto Sales

Amazon, the Seattle, Washington-based multinational e-commerce company also specializes in classic cars, antique cars, muscle cars and specialty cars. Known as the Mecca for online shopping of books besides DVDs, CDs, MP3 downloads, software, video games, electronics, apparel, furniture, food, and toys, Amazon Auto Sales, also caters to thousands of automotive enthusiasts as they purchase, sell, restore and maintain their most prized possessions.

4.       Classic Cars

With more than 10 million car shoppers each month, ClassicCars.com is the leading destination for online car shoppers. The Web site offers credible and easy-to-understand information from consumers and experts to help buyers get the best information on what to buy, where to buy and how much to pay for a car. ClassicCars.com provides comprehensive pricing information, side-by-side comparison tools, photo galleries, videos, unbiased editorial content and a large selection of new- and used-car inventory, and gives the car buyers the liberty of their shopping process with the information they need to make confident buying decisions.

5.       Auto Trader

AutoTrader.com can be your ultimate online solution for buying and selling new, certified and used cars. It's a Web site that is designed to give you more control of the buying process and makes finding a vehicle easier than ever before. AutoTrader.com is the only Web site with more than 3 million vehicle listings from 40,000 dealers and 250,000 private owners. The site gives you the largest selection of vehicles and attracts more than 14 million qualified buyers each month.