Zotero has a desktop app in addition to their original Firefox extension. Personally, I've been very happy with it. I have my articles stored in JungleDisk, and

Zotero has a desktop app in addition to their original Firefox extension. Personally, I've been very happy with it. I have my articles stored in JungleDisk, and everything syncs between mac laptop, windows desktop, and ipad (with ZotPad on the ipad).