Great discussion, thanks. I was first introduced to EndNote as an college student in the late 1990s. I appreciated the concept but found having a separate application for reference management to be more of a burden than a boon since I used my computer's file system (and my physical file system) as the primary means of keeping track of materials. For me EndNote never really went beyond the promise of what such a program could do. The Zotero vision has an edge, in my opinion, because (1) it seems to be designed with an eye to the workflows that people actually use (browser » word processor » browser, etc.), (2) because it's open source (especially being a Firefox extension), and (3) — as you said — because it's open standards.