I currently run Xubuntu on my old desktop with the same specs as you. It’s based off Ubuntu (the most popular Linux distribution), is very fast, and is easy to use.
You can also try Puppy Linux or DamnSmallLinux.
Gregory Allen Mansheim
That depends; are you willing to sacrifice all of the bells and whistles of a pretty interface for speed?
There are many “bare bones” versions if you’re up to the challenge.
Try this link, and see what you are most comfortable using.
I thoroughly recommend Linux Mint 7 XFCE which is built upon Ubuntu 9.04 and is ideally suited to older Hardware Its easy to install and easy to use plus it comes with much of the software you are likely to need preinstalled