Rental fees: €9.95 for seven days of access to one movie, €26.86 for three movies or €42.28 for five movies, either streaming or download. If you prefer not to use a credit card, you can pay by the minute through a dialer program (the site currently services the U.S., U.K. the Netherlands, Switzerland, Germany, France Belgium, Italy, Australia and Spain). Or join Private Clips and purchase individual scenes starting at €2.95 per clip for seven days of access. Private also sells its DVDs online at a discount. Relative size of selection: 1 of 4 stars (the site offers only Private titles). Technical requirements: Windows Media Player or DivX. Credit cards accepted: Visa, Mastercard (billed as PR-VTE). Privacy policy: You can opt out of having your information shared with third parties. Customer service: Email.

Best Adult VOD Site?: The most popular VOD service in our guide is Hot Movies, which has tens of thousands of adult titles. You can buy access by the minute (at 8 cents and up) or purchase unlimited viewing of any individual title for two, seven or 30 days. Our most popular flat-rate site is Video Box, which charges $9.95 per month for unlimited downloads from its library of more than 3,000 movies.

Prefer to Rent DVDs?: If you prefer to rent DVDs rather than download movies, compare online services at our Adult DVD Rental Guide. Most charge $10 to $30 per month to have one to three adult DVDs out at a time, with no late fees or return dates. A few rent individual DVDs for $3 to $5 each per week. A credit card is required to join any DVD rental service.

Discount Adult DVDs: If you're looking for bargains and selection, we suggest Movies by Mail, which offers new customers a free movie when you pay $4.95 shipping, as well as discount codes (see site), XRent DVD, which sells ex-rental titles from $4.50 each or Overstock DVD and Adult DVD Empire, each of which have many clearance titles and offer free shipping on every order.

Video Gold Adult DVD Club: Choose two adult DVDs for $5.95 each plus shipping when you join the Video Gold Adult DVD Club from Adam & Eve. You'll also be able to choose a third adult DVD free. As a member, you must purchase two more DVDs at regular club prices within a year. Or purchase a fourth DVD when you sign up for $19.95 and buy just one additional DVD within a year. Open to: Residents of the U.S. and Canada.

Search for Sex Books: Browse the list of sex book bestsellers at Amazon.com, including The Adult Video News Guide to the 500 Greatest Adult Videos of All Time.