I've recently restored an original Eeepc to working condition by install lubuntu. I can't believe what a difference an OS version makes to the running of the computer.
Lubuntu is a version of ubuntu (the most popular linux distrubution) with a really stripped down windows experience (LXDE for those interested). The total memory usage for the windows manager is about 50 MB! All the normal progams work on the system and it is good for old hardware
I use Lubuntu on all my computers, I just like my computer to feel responsive and snappy and i'm not really interested in my computer looking flashy and sparkling and taking 10 mins to search/open a file
ARRRGH - I've turned into a middle-aged Computer user!!