While you can no longer buy a PC with Windows XP pre-installed, there are still ways for you to get it… but only until July 31, 2009.

Due to a clause in the Windows Vista legal rules, if you buy certain levels of the Vista operating system, you can legally downgrade to Windows XP.  (In this case, it might be considered an upgrade…)  This deal was originally meant to expire on January 31st, 2009, but due to demand from manufacturers, it has now been extended to July 31st of next year.

The best case scenario for doing this is having the manufacturer do it before you receive the computer to save yourself the hassle.  Most companies do offer this service, but only on select models and levels of the Vista OS.  Make sure to read the description of any system you are ordering, and also make sure it is one they offer XP on.