[kumarsw]

JabRef. No cloud component and as a bonus the database is just a BibTex file which you can keep in Git.

[acidburnNSA]

There a zotero plugin that stores the entire contents of your zotero db as an auto-updated bibtex file too.

https://github.com/retorquere/zotero-better-bibtex

[growingkittens]

I don't know much about JabRef itself, but a quick search seems to indicate that one of the key differences is word document integration - JabRef is focused on bibtex.