Open Profile Folder 1.1.5 Rated 5 out of 5 stars
Does it's job and does it well. This allows you quick access to your profile folder on your computer. Sure this feature is already built into some extensions, but if you need this feature without a million other things thrown it (i.e. bloatness), get Open Profile Folder.
What's not advertised though is you can use this add-on to quickly make a backup copy or your profile folder in the event your profile ever corrupts and loses some of your data. Then all you do is boot your corrupt profile out and replace it with the backup. This add-on makes backupping/replacing a snap.
Though please be careful when in your profile folder. If you mess with things you see, you may wreck your profile and have to either replace it or make a brand new profile from scratch. Anyways despite the potential risks, I give this a 10. Very useful add-on.