I recently converted a good friend of mine over to Zune. He has been an avid iPod user for years, and is now singing the praises! It's funny, when I convert someone over to Zune, they always seem to find a feature that they love, that I tend to take for granted. He came up for a visit this weekend and he was showing me all of the new songs he had found on ZunePass and was showing some pictures of an event we attended last December. I didn't have most of these pictures and I wanted them in my collection, so I connected his Zune to my PC as a guest device, went to the device view, and started right-clicking the pictures I wanted, and chose to copy them to my collection. Pretty soon I had all the pictures in my collection and we were viewing them on my 24-inch monitor. "Sweet!" He exclaimed, "Does it work with music, too?" "Indeed!" I replied, and I then grabbed a few albums from Radiohead's Towering above the Rest collection from his Zune and added them to my computer*. "I could never do this with my iPod, this is awesome!" *note: I already own the album.
And there it was. I could have sold him on the Zune last year had I told him about reverse sync, a feature that I totally take for granted, but is yet another differentiator for Zune. With reverse sync, you can copy any music, videos, or pictures (just no Podcasts or playlists at the moment) from your Zune device, right onto your PC- extremely helpful if you have multiple PCs and more than one Zune. Sorry kids, you can't do that with iTunes.
Reverse sync, a graphical journey...
First connect your device and click the device icon in the lower left corner:

Now, once you have clicked the device icon, this will take you to the device view where you view all of the content on your device. Notice how the background changes and takes on a hue that's similar to the color of your device:

Once here, now you can select the different headings to view your music, videos, pictures, podcasts, and friends. You reverse sync in much the same way as your perform a regular sync, just drag and drop a song, album, artist, genre, video, or picture to the collection (computer-like icon in the lower left corner.) Or, you can also right-click any of those objects and choose "copy to my collection":

Voila! The content you have chosen has been copied over to your PC...
Reverse sync is not only quite useful for sharing media with friends, it's also great knowing that you always have an easy backup plan to restore your media if you get a new computer, or you have a drastic hard drive crash. I tend to use it most often when moving content between 2 computers, say my home and office machines. I can take my Zune, connect it to my office machine as a guest device, go to the device view, then drag and drop a few albums to the little computer icon in the left corner (you can also right-click and choose "copy to my collection"), and voila, new albums on my office machine. Note that you don't have to connect as a guest to perform a reverse sync, I just mention it as that is the most prevalent mode reverse sync is used in.
So, if you are already hip to the reverse sync, good for you, and feel good about having a Zune! If not, move some files to a new machine, share a home movie with a friend, or just otherwise make your iPod friends jealous that you have yet another feature that they don't. :)