Keepass is also (correct me if I'm wrong: I'd love to hear there is another) the only password manager I know of which is fully cross platform.
I like keepass, especially since there are so many ports of it to so many platforms. However, if someone is looking for something more akin to lastpass, here's a few open source ones:
http://www.fpx.de/fp/Software/... - Password Gorilla (also on github: https://github.com/zdia/gorill...). It's also open source, but it's a TCL/TK application. I'm not sure what their andriod status is (there is some info on their site regarding use of HECL to port the TCL parts to android, but I don't know the status).
https://www.passpack.com/ - Passpack works on chrome, firefox, ie, and safari. It's similar to lastpass in many ways. It's not fully open source, but they did open source a bunch of the libraries they use/made (aes/rindael, xxtea, json2, sha-256 in js, etc: https://code.google.com/p/pass... ).
https://www.passlet.com/ - passlet. The SSL cert for that site expired in 2010, so I don't think I'd use this, but it is cross platform and built according to the host-proof-hosting concepts. They open sourced their PBKDF2 methods: http://anandam.name/pbkdf2/
http://aaronboodman.com/halfno... - halfnote is just a notepad, but it's encrypted in browser, and it's open source (https://code.google.com/p/halfnote/)
All that said, I'd probably stick with keepass and/or lastpass.