For years, I've happily used Powermarks: http://www.kaylon.com/power.html
. This modestly priced shareware is the best bookmark manager/organizer I know. No more dragging bookmarks to a category, no more forgetting what category you put a bookmark in. Powermarks is extremely fast, efficient, easy to use. You can use it with Netscape, Internet Explorer, Opera, Firefox, Mozilla, and/or NetCaptor; if you change browsers, you needn't worry about moving your bookmarks/favorites. It integrates with all these browsers, I think. I routinely use Firefox and Opera, and from time to time IE 6, and Powermarks gives me access to all my bookmarks (about 3000 of them) no matter which browser I use. And I can find any of these 3000 bookmarks in about one second. I love Powermarks!