Placing your computer into a stand offers two distinct advantages: it minimizes the profile your machine takes up on a desktop or shelf, and it offers more air exposure along the sides to help keep your system running cool.
NewerTech's NuStand Alloy line ($25 Apple TV, and $25 Mac mini) provides sturdy aluminum stands that have a pleasing heft. They look great and felt good in my hand. They offer non-scratch silicone inserts to hold the devices as well as four stable rubber feet. Design-wise, these are practical and useful.
Of course, there are some disadvantages to using vertical solutions like the NuStands. Placing all the ports into a vertical line means your cables tend to run over each other as they hang down from the side. In addition, you tend to see the side of the Mac that Jony Ive really didn't want you to have to look at. In the case of the Mac mini, this is the black circle of the user-service port. While not ugly, it's not exactly something you may want to look at all day.
Of the two units I tested, I much preferred the Mac mini NuStand Alloy. It provided space-savings convenience on my desktop. Once all the various cables were plugged into the numerous ports on the back of the mini, however, it wasn't nearly as pretty as the product shot you see in this picture. Things can get pretty busy on the back of a working computer. The "last open USB port" problem is magnified by cable clutter.
The Apple TV NuStand Alloy didn't work as well for me. It took a tiny device that's engineered to be almost zero-profile, turned it on its side, and actually made it obtrusive. The stand itself was just as well made as the one for the Mac mini; I just didn't find any compelling purpose for it.
If you're in the market for vertical computer stands for the Mac mini or Apple TV, the NuStand Alloy products will not disappoint. They're well-made and offer exactly the functionality advertised.