I've fallen in love with del.icio.us. Not only is it a nice way to have my bookmarks available from any system, it is a snap to add a new bookmark and categorize it. And it is an endless source of other URLs that other people consider worthwhile. From your bookmark page you can explore sites that others have similarly tagged.
Oh, yeah, it supports RSS feeds! Subscribe to my bookmarks , just my 'linux' related sites, everyone's everyones bookmarks or everyones linux bookmarks . Sweet use of RSS.
(Not to mention a sneaky way to point folks to the most disgusting video I've ever see on the net. Don't have any food in your mouth when you watch it! Come to think of it, you may never want to eat again.)