You don't need Windows or Linux to install Android (well, apart from to create a bootable disc or USB stick) -- it's an operating system.
I've loaded it into a virtual machine using VirtualBox and it actually seems like it could be usable with a mouse and keyboard but since it can't be made to go full screen in VirtualBox due to lack of drivers I couldn't test whether it would feel any good day-to-day. However, as business_kid points out these phone and tablet operating systems are locked down in strange and arbitrary ways which could make them frustrating to use on a day-to-day basis.
If you are interested you can find out more about running Android on your PC here:
You could also take a look at Chrome OS the OS that Google developed to run on more traditional laptop devices.
(Thanks for bringing this up you reminded me to take another look at ChromeOS myself)