Even with the Pentium M in the Thinkpad, can I run Netbook Remix? Their documentation states an Atom processor.
If you really want to stretch your brain install one of the BSD's and use that as your desktop for a while.
If you load up FreeBSD or OpenBSD and work through the documentation and stick with it for a couple of months you will be a better system administrator and a better developer because you will have been exposed to some of the different ways of solving the problems of building an effective operating system.
i started freebsd (5.3 iirc) like 5+ years ago and abandoned it for openbsd 3.6. do i miss anything?