Whilst working at a copy-shop late last year/early this year, they were throwing away a whole bunch of old computers, monitors etc. I got to take home a desktop which couldn't have been
too old (given that it came with Windows Vista). The gamble paid off: although I couldn't use the Windows installation on it (which I'd only want to use for iTunes, just for the record), due to not knowing the password, I installed Linux on it, and it's worked perfectly so far. The 2GB RAM and 160GB hard drive aren't the latest and greatest, but they're quite sufficient. Although it's almost four years old, I'm glad to have rescued a reasonably modern, fully-functional computer from being scrapped! It has Linux Mint 9 (the most current Long Term Service release), which purrs away nicely in the background...
Linux desktop by
transitmapsetc, on Flickr