Microsoft created a problem for itself with Vista, prompting many users to stick with Windows XP. People have been using XP for seven years now, and regardless of how good Windows 7 might be, many might have a hard time leaving their security blanket behind. I've been using Windows 7 for months now, and I really like it, but there a number of reasons why XP users might want to stay put a little longer.
Extended support until April 8 2014. It's true that Microsoft has discontinued mainstream support for XP, but for most people this matters little. Microsoft will continue to provide security patches and per-incident phone and Web support for XP for years to come.