Windows is dead, long live Windows!! It was sure to happen one day, and that day is here.
Microsoft have in beta the next version of the Live products such as Live Messenger, Live Photo Gallery etc. Windows XP is no longer supported, and furthermore Live Essentials 2010 Beta will not install on XP at all.
I struggled installing the latest Beta on an XP computer and got an error that said the installation file was not a valid win32 application. When I visited Micrsofts website I saw that Vista is the oldest version of Windows this suite of products will run on. (It would be nice if the installer simply informed you that windows XP is no longer supported).
One reason XP has continued to be used for so long is that it does what most people want from a computer and all applications run fine on it. Microsofts past plans to retire the product were met with resistance and they kept it alive, at least up to now. Live 2010 products will be the first Microsoft products to spurn XP. This is the first nail in the coffin for XP. As more applications from Microsoft and 3rd parties are released without the possibility to run on XP, the need and desire to upgrade will increase.
Office 2010 runs on XP, so corporations may still be able to put off upgrades for a while yet, home users will be the first pushed to make the upgrade since the Live products are targeted at them. The latest Live products have built in integration points with social networks like Facebook, so the desire to use the latest Live products will be compelling for many home users.
Moving off an 8 year old platform is advisable anyway IMHO. Windows 7 is a good OS and is worthy of taking up the reins from old faithful, Windows XP.
Update: 2010-09-17 IE9 Microsoft latest internet browser is in Beta. IE9 does not support Windows XP. The pressure to move off XP will build once people want to get the new features in the new browser.