I’ve installed Crunchbang Linux on the old Thinkpad X24. It’s based on the Openbox window manager, and it is faaaaast, and so far very pleasant to use. The only issue I encountered was Openbox’s reliance on the super key (aka the windows key, which the X24 doesn’t have). This is easily solved though, thanks to this blog post at iceflatline. w00t.
Update: It turned out to be a little different, the script example in iceflatline needed to be tweaked slightly for my setup. The command
xmodmap $HOME/.Xmodmap
is a useful one – it pointed me to an error that was preventing the new binding from working. A useful article on Xmodmap can be found here.