Zotero is a free, easy-to-use Firefox/Chrome extension or standalone program to help you collect, organize, manage, search and cite your research sources directly in your favourite word processor, with 300 MB free online storage.
- Consistent research sources management. No hidden fees. Nice UI.
- Probably the best open source alternative to Endnote, even though it does lack some functionality. Most notably, it lacks the ability to make composite references (ie reference 1 a)... b)... c...). However, from a privacy perspective and the fact that its excellent browser plugins can save information conveniently, it's still highly recommended.