Nothing wrong with public domain. =) I've been using zlib, and I also like MIT. A common one on the wiki (which I also once used) is RWPCL. I actually posted some thoughts on licenses a while back here: Archived_talk:User:Voidious_20110909#Choice_of_license. It's definitely up to personal preference.
zlib, MIT and Creative Commons Attribution all look nice to me as "credit where credit is due" permissive licenses.
The smoother method I'm hoping to use is from a talk page here on RoboWiki. RoboWiki:Copyrights is blank, so I'm not sure how to proceed with that code.
Should have this code in a testable state, hopefully with a test painter bot to squash bugs this weekend or on Monday, depending on how life goes.
Anything without a license listed is probably free to use as if it's public domain. I think we stumbled on deciding on a license for wiki content because so much of it was added before any license was specified, so it seems wrong to try and retroactively add a license. Very good point that we should update RoboWiki:Copyrights, though, given how prominently it's displayed.