I've been using Foxmarks a bookmark synchronizer for FireFox for the last year or so.
Its just this little icon on the corner of Firefox
It is fantastic, it kills del.iciou.us by a mile. It so easy its just totally behind the scenes and I can organize my bookmarks using the standard bookmark manager. Check it out if you can. No crappy extra menu like delicious which, when i last used it, had no sub menus and i had to regroup/organize every single one of my existing bookmarks. No way! They lost me.
Firefox is my browser of choice because it forces Microsoft to innovate and competition is a good thing. I encourage everyone to download Firefox and use it as their primary browser with Foxmarks as their bookmark synchronization program, if for no other reason than a monopoly on the internet is not a good thing. I don't mind there being big players and small players but without a critical mass people won't write their pages to work with Firefox, so no one will use it, so there will be a real incentive for Microsoft to create proprietary standards. I'm assuming you are the technical elite or why are you reading a blog on software? Go download Firefox, so it keeps its critical mass, which will keep standards Open and maintain internet diversity.
Its Free! 10/10 Foxmarks! Get Firefox.