XP Pro will be supported by Microsoft until 2014. Support for all other versions of XP are being dropped in 2010, although rumors have been circulating MS will drop support late next year.
Drivers are always an issue, especially if it is a laptop, but general driver support for XP will continue for many more years. It is still the lion share of the MS OS install base.
I agree extended support will be available until April 8, 2014 but isn't mainstream support stopping on April 14, 2009 which most of the current "home" (XP Pro, Home, Media etc) users will fall into. From the bulletins I get from MS and the MSDN community, drivers on new product entering the market will not have a working (stable) inf file for any version of XP. I have had this discussion with my eVGA, ASUS, Gigabyte reps amongst others they are basically saying the same thing for their video cards, motherboard and other peripherals.
Please correct me if I am wrong here.