One more vote for Zotero. It is an awesome nifty software, that I liked more than Mendeley. Yes, you will have to install Firefox plugin. The built-in features automatically pull the paper name, and tag authors too. I got fed up from downloading 4fgh7u.pdf names from ACS sites, and Zotero solved the name tagging, then collating into directories and sub-directories very easy. You can save webpages too etc. I totally recommend it.