[bensandcastle]

xkcd store has some good ones,

Here's a few I've been planning to have printed:

Human Spaceflight, everything to scale http://theorysend.com/uploads/bdcffe08190411f5095eabcc8860d3... from: https://www.reddit.com/r/space/comments/2niljz/human_spacefl...

Tree of Life, over time: http://e.fastcompany.net/multisite_files/codesign/slideshow/...

Evolution of US politics: http://xkcd.com/1127/large/

I was planning to get most of these printed on a board of some kind, so they be more durable than posters, although I haven't chosen a supplier yet.

Depending on your use of the poster and the printer you go with you may need a rights release from the artist, so often it's easier to find a commercial print and get it framed, if you are willing to have all that glass.