if you want to teach yourself a new OS I would suggest Linux, the powerful command line allows you to have the system exactly as you wish.

I think of the graphical based OS's as being communication with the system on the computers terms, you can only click what the computer presents to you and nothing more it leads the communication.

With a command line based OS you can enter commands to which the computer responds which means you lead the conversation.

Linux has a number of different desktops to use to suit your needs and nothing is cooler imho

Have a look at the beyrl desktop, makes Vista and OSX graphically poor

http://www.youtube.com/watch?v=2eDI4-IH58s

And Linux is FREE