Second hand Thinkpads run Linux beautifully. Recently picked up a T430s off the bay for around 130. Hardware support is pretty much the same across distros as they share the kernel, support for Thinkpads is particularly good as they are used by some of the developers. Only downside is that the TN screens on Thinkpads are pretty bad for viewing angle.
I like Solus as a standard install and go distro, but you could pick from Ubuntu, Mint, Fedora etc - Whichever takes your fancy.
