Here is one for web developers or those of us who use more than one browser (for whatever reason)...
Compass Bookmark Manager
Quote from site: "It supports three most popular browsers - Netscape, Internet Explorer, Opera, and also any generic browsers specified by the OS. What makes Compass unique is the power of handling the hierarchical structure of folders. With Compass, you'll be amazed how easy you can find and organize your bookmarks the way you want, and how easy you can integrate all bookmarks from different computers or different browsers. Not only is Compass a bookmark manager, but it is also an "outline editor" or a "note editor." You can use Compass to create your personal journal, notes, outlines, memos, ? etc. When you use Compass as an outline editor, you will find Compass is even better than the programs that were created for that purpose. Compass can easily handle more than thousands of bookmarks. Compass has been tested and works with Netscape 2.x - 4.x, Microsoft Internet Explorer 3.x - 5.x and Opera 3.x - 5.x on Windows 95/98/Me/NT4/2000."
I use it and really like it.