Vim offers strong file encryption with Blowfish
http://blogs.techrepublic.com.com/security/?p=4870
Haven't looked into it much, yet. On a Windows machine, today, where I did notice that it seems to bork tab-based autocompletion when specifying a filename while saving (^I doesn't trigger autocompletion).
EDIT: Credit due to:
http://www.reddit.com/r/vim/comments/ey0ma/vim_offers_strong...