Zotero

Slight learning curve and will take some getting used to but really like the Chrome button for quick capture of references.

I love that it automatically pulls in the reference data when you input the DOI or ISBN. Unfortunately, you still need to double check for accuracy. If the title is not capitalized correctly, or other minor errors are in the citation Zotero produces will be wrong. Garbage in, garbage out! It's also been useful to me to input notes as I read and use tags to help sort and categorize references. Another handy tool is the ability to save a snap shot of a web page.