I maintain that Slackware is the ideal Distro.

But i would recommend Ubuntu or Xubuntu for you purpose

I like Slackware and have installed it on an old laptop with 96Megs of Ram and 4gigs of hard drive and only a 266 mhz processor. I had to use Fluxbox and lightweight applications but it ran fairly fast. Your computer should run just about any distro fine with an adequate swap partition. I would recommend the Debian based Freespire. It has a lot of the proprietory software which is lacking in most distros. I love the open source community and applaud what they are doing. So I hope this isn't taken the wrong way. But I noticed that in the original post a lot of Windows users would be using the computer. Give Freespire a whirl, it should be an easy transition from windows to Freespire.