Another question that has been asked. People are ether too cheap or don't have room for more then one computer but want to share one system and still have the functionality of multiple systems. This is called Multiseating. So far only Linux/Unix can do this. There is a rumor about Windows 7 having this function but with our luck the system would be bogged down from all of the typical Microsoft bull.
Older multiseat systems needed two videocards but with better driver support these days you can do away with one video card that has dual outputs.
In all you need a typical home PC with a aftermarket card and dual video out, two keyboards, mice and two monitors. A lot of people prefer to use a PS\2 style keyboard and mouse as primary and USB as secondary to keep the setup simple.
Of how the software works is the primary user logs in the second user under SSH with xorg frontend on video 1. The keyboard and mouse is bind to the second user as well. With proper permissions and code you can make it load up when the systems boots
It is. Windows 7 utilizes the same GUI that Vista used except the requirements are astronomically lower. For example, I have 8GB of PC8500 in my machine right now. Idling, Vista fully used about 1.7-1.8GB of that.
I'm running Windows 7 right now and it uses about 500-600MB, and looks a lot better than Vista did. In fact, the interface and options are great.
I will go as far to say from using Linux, Mac, and Windows the last several years that this is one of, if not the best, OS created for mainstream use. By far.