Microsoft officially stopped selling Windows XP as of June 30, but retailers can keep selling it as long as they have copies. Perhaps as a result of its potentially impending scarcity, XP is near the top of Amazon.com's software list, with the full version of XP Home at No. 15 and the full version of XP Pro at No. 21.
The highest ranked Vista edition doesn't crack the top 25, although it does come on nearly all new PCs these days so most people don't need a boxed copy.
Source:→ CNET News