Windows Home Server and Windows Server 2008 aren't really comparable operating systems. Windows Home Server is designed to do certain things well, but it's not a general purpose server OS that you can easily or safely tack just anything onto. You would do well to review the materials on the
Windows Server 2008 section of the Microsoft site, and on the
Windows Home Server section.
Now, for your specific questions:
- It's possible to install P2P software on Windows Home Server, but doing so is not supported. And in either case, you will need to choose P2P software that supports remote management if that's a factor for you; neither will make this any easier.
- Windows Server 2008 doesn't have much in the way of client backup tools. Windows Home Server does.
- Imaging: Windows Home Server effectively backs up disk images. You need to be aware that, when restoring such an image, installing on a new computer may not work. This is much the same as taking the system drive from one computer and putting it in another. It may not (usually will not) work. For your stated purpose, however, Windows Home Server will do what you need.
I'm not on the WHS team, I just post a lot. :)
