Free overnight shipping and a speedy buying process enable Outpost.com to fend off Amazon.com and remain the leading Computing site in the latest PowerRankings by Forrester Research, Inc. (Nasdaq: FORR). Forrester PowerRankings combine survey data from online consumers and unbiased shopping tests to provide objective rankings of the leading eCommerce sites in various categories. Following Outpost.com are Amazon.com, Staples, Beyond.com, Micro Warehouse, buy.com, CDW, Egghead.com, and TigerDirect.

In addition to free overnight shipping, Outpost.com offers low prices and first-rate customer service. Its site also makes registration optional and shopping simple. Its greatest weakness is the lack of basic features, like a wish list and gift-wrap service. Although a newcomer to the Computing category, Amazon beats most of the competition with lower prices, personalized recommendations, and one-click checkout. However, mandatory registration and no real-time inventory information can leave shoppers frustrated.

“Since our last Computing rankings, Outpost.com has increased the distance between itself and the competition,” said Tom Rhinelander, senior analyst at Forrester. “If basic features were added to the already strong online experience, even No. 2 ranked Amazon.com, which only started selling software last November, will have a way to go before catching up to Outpost.com.”

Third-place Staples also offers top-notch customer service with timely email and phone responses, as well as free shipping and an effortless return policy. However, post-purchase out-of-stock notification, inaccurate searches, and inconsistent navigation can be frustrating for consumers. As a result of optional registration and express checkout, Beyond.com lands in fourth place. Primary weaknesses consist of missing basic features like a wish list, address book, and reviews.

Micro Warehouse comes in fifth, offering speedy email responses and impressive product comparison features, but its buying process is laborious and prices are among the highest. Significant improvements to its organization and site navigation weren’t enough for sixth place buy.com. Mandatory registration, no real-time inventory information, and slow customer service leave a less than favorable impression.

CDW lands in seventh place due to high costs, server errors, and a frustrating buying process, although it offers solid customer service. Landing in eighth place, Egghead.com offers real-time inventory information but lacks an effective search function and lists high shipping costs. Confusing and disorganized product information, the highest shipping costs, and no shipment confirmation email leave TigerDirect in last place.

For the updated PowerRankings, Forrester surveyed 19,000 consumers from Greenfield Online’s 600,000-person online panel. These consumers identified the most recent eCommerce sites that they purchased from and rated their experiences. A team of Forrester shoppers then evaluated the shopping experience for sites with a statistically valid number of consumer respondents, performing a series of rigorous tests in six areas. The consumer data and Forrester shopper scores were then synthesized and weighted, with consumer views accounting for two-thirds of the overall PowerRanking. A complete set of their own PowerRankings results — both consumer and Forrester shopper data — are made available to all ranked companies for no charge.

In the coming weeks, Forrester will be announcing results in additional PowerRankings categories. Additional information about each of the categories, including a complete set of rankings and scores, can be found at the PowerRankings Web site — powerrankings.forrester.com.