Much to mixture's chagrin, I plan on running my XP machine until it dies.
Now before the ever so helpful and knowledgeable 'mix' gets all riled up please let me explain. I purchased this ASUS EeePC some 5 years ago with the intention of it being a sacrificial net surfing machine. The computer is not powerful so I had to turn off many Windows services to make it run to my liking. I do not run virus protection software although I have occasionally installed a free version when my suspicions were aroused only to find nothing, then I uninstall it. I only use the windows firewall that came with XP for internet protection. I do not install Windows updates.
Other than Windows XP the little NetBook also runs FireFox 26, Office 2003, VLC, Quicktime, Photoshop (old version), vim, Winzip, Cygwin and Kyodai Mahjongg - that's quite a punch for a little tacker - and they all work well enough to be useable.
I have recently setup another W7 laptop to become this one's replacement should it eventually croak. After 5 years and many net hours of use, the little EeePC is showing some physical signs of stress. The power supply plug has been replaced 3 times. The batteries are almost unusable and confusing the run-on-battery mode OS feature. Sometimes I can even hear faint electrical arcing noises emanating from the back.
But I will persist with it dammit....until its very last CPU cycle regardless of what those Microsoft people say.