Slackware 15.0, my computer is very old (intel q8300 + 4gb + nvidia gt218). I like slackware for its simplicity (KISS) and it also has a more limited out of the box number of packages compared to debian, ubuntu, arch and gentoo. I consider this an advantage, because a lot of people are distro hopping and when I gave up on distro hopping, and used debian for a while, I just started trying different progams that had the same/similar functionality. With slackware I try to make due with what is provided and that gives me peace of mind :-)