[ericbrow]

I'll second Mendeley. I've used several other options, but Mendeley has a Chrome plug-in that will download the PDF as well as try to read author and other bibliographical info. The desktop app helps in searching for key words within all documents as well as individual documents.

[Y_Y]

Combining the mendeley plugin with the automatic .bib generator and LyX means I can cite stuff pretty much as quickly as looking at the page.