When my mother-in-law's Shuttle went on the blink, I replaced it ($85, Craigslist) and switched her from Ubuntu Edgy to Debian Squeeze, Firefox 2 to Iceweasel 3. She's happier now.
I've installed Squeeze candidates twice. Both times, I tried to install it from a USB thumb drive. Both times, the BIOS insisted it could boot from USB, but did not recognize the Debian boot image as something to boot from. Both times, I ended up burning a CD. Both times, the installer ignored the packages on the CD, and instead demanded a network connection, and installed everything from a mirror.