So this morning I started using Zotero ... and I think I might like it. As you may know, Zotero is a plugin for Firefox, so it allows you to collect citations, export bibliographies (drag-and-drop, man), and keep notes right in your browser window.
In addition, Zotero creates funky little time lines based on the citations you have in a reading list, so you can visualize when the stuff you've found was published in relation to everything else.
What I'm less crazy about, using Zotero, is how time consuming it will be to import my existing records (six years worth) from Endnote and Filemaker Pro. It looks like I can do it, but lining up the fields in the merge will take some time.