I'm a heavy KDE user but I keep switching DEs and WMs every now and then. Currently I'm playing with Enlightenment which is as pretty as it always has been. More importantly, it starts up on my aging laptop in less than 2 seconds, which is years ahead of both Gnome and KDE. As another lightweight but full-fledged alternative to the big two, I recommend it highly.

Great list. Some other good mathematical non-ficiton books I've liked are:
Anything by Marcus du Sautoy (Music of the Primes, Finding Moonshine)
Dr.Riemann's Zeros by Karl Sabbagh
Unknown Quantity by John Derbyshire
Alex's Adventures in Numberland by Alex Bellos

While this is a very interesting finding, I think the hermit crab's use of empty snails' shells is an already known example of similar tool use in an invertebrate.

Your comment made me think of what first attracted me to the Free Software world. To any one who's discovered the elegant beauty of Darwin's evolutionary theory, there is an equal attractiveness in the way the GPL license is framed.
The very fact that the GPL attaches itself to the code its released under, and survives into the downstream modifications that are made to the code.. there are beautiful resemblances to the way successful life itself evolves.
I'm inclined to believe that licenses that are not viral (e.g. BSD) and depend on altruistic reasons to survive, are somehow doomed to extinction (i.e. will be swallowed by proprietary licenses that couldn't care less about perpetuating the BSD cause). In the long run, the GPL will emerge as the fitter license that made its way into the larger user base while retaining pefect copies of itself.
(Of course I'm neither a biologist nor a programmer, so apologies if I sound like I'm talking outta my ass.)