Mountain Manages External Volumes from Your Menu Bar
Mac: Unmounting devices in OS X isn't exactly hard, but Mountain is a tool that makes it a little easier by giving you control over all your external volumes from the menu bar.
Mountain sits quietly in your menu bar until you need it. When you need to safely eject an external volume, just click Mountain and you'll get the option to eject one or all you mounted volumes. It also has a few tricks up its sleeve, including the ability to quit any apps that are open, mount all drives that are connected on startup (and unmount on sleep), and blocking you drives from being disconnected and notifications for when it's safe to unplug.