I think I'm pretty typical in that I use a desktop computer in my home office, then grab the laptop on the way out the door. I do have good tools for syncing files and folders between the two, but a glaring problem has always been my browser. I've manually set up my bookmarks toolbar on both machines, and they wind up being just different enough from one another that it is a distraction. I've given up on keeping bookmarks like I used to. Delicious is cool, but not really the right tool for keeping a nice, tidy, hierarchical library of bookmarks. I rely heavily on my browser history (yay AwesomeBar!) to find recently used pages, and I often wind up having to try my searches on two machines if I can't remember which one I was using at the time.
Enter Weave. Weave is a Firefox add-in that synchronizes not only your bookmarks but your saved passwords, browsing history, and even your open browser tabs. If you don't like any of these, you can pick and choose.
Setup is quick and easy, but make your choices wisely about overwriting data on other machines! I erred on the side of caution and regretted it when my first sync led to having two copies of most of my bookmarks.
An immediate concern was security and privacy. This is sensitive data! You can store your data on Mozilla's servers and access it securely over SSL. If you are a little more paranoid and technically inclined, you can run your own Weave Server. Toby Elliott has put together a tiny minimal version of the Weave server, or you can go with a full on version from Mozilla. If you just want to run it for yourself, or maybe a handful of friends & colleagues, the minimal version should suffice, and is a quick setup.
Note to friends and colleagues: I've set up a secure weave server, if you'd like to hook up to it (i.e. if you trust me more than Mozilla), please just let me know.