I got this for the exact reasons you describe: http://www.thinkgeek.com/homeoffice/posters/6a93/ The night effect just seemed really cool to me... I love this poster... it's also much better seeing it in person - I don't think the TG site's picture does it justice.

I also like the Linux distro time line poster that used to be linked from here to KDE.org: http://www.codinghorror.com/blog/archives/000842.html Not sure what happened to it, but if I could get it I would.