Alternatives

If full profile syncing isn't your goal, there are a lot of good tools available for other forms of Firefox synchronization (though none boast extension syncing). We've always liked Foxmarks for bookmark syncing. On the other hand, the popular Google Sync extension syncs bookmarks, passwords, history, and browsing sessions, but stops short of extensions.

FolderShare is Windows and Mac only, but there are other Linux-friendly sync tools available, like Unison, that would likely work, as well. I haven't spend a lot of time using this sync method, either, so there may be a few hiccups here and there that I'm not aware of. Additionally, there may very well be a better option for tackling this whole process, so if you've got a streamlined method for keeping your extensions and more synced across computers, let's hear how you do it in the comments.