I just loaded Puppy Linux on my 6.5 year old IBM Thinkpad and suddenly it's like a whole new system. I can't watch online videos on netflix (though that function is still in beta testing for Macs too), but I can listen to Pandora online, browse using something derived from firefox (I actually like it better than firefox) and everything opens up significantly faster than with XP. Connecting to my secured wireless was surprisingly quick.
For how I'm running puppy, I just went on their site (
Puppy Linux), downloaded the ~90 megabyte free OS, wrote it to a cd using the recommended freeware program, turned off the computer and upon restarting the computer went into the BIOS and told it to check the CD before the hard drive. I'd never tried linux or any other operating system aside from Windows before, and am not extremely computer savvy, but aside from the download time everything was easily done within 15 minutes thanks to good instructions along with small size and an intuitive setup.