This is a short sharp and shiny list of things that I can easily do in Linux but find it hard or impossible to do in windows.
Connect more than four people across the internet to a graphical interface at the same time.
Tinker around with the source code.
Compile my own Linux from scratch.
Have as many or as little programs installed as I want.
Change every aspect of the user interface to suit my needs.
Never pay for any program.
Use more of my memory for programs and not for the operating system.
Use less than one gigabyte of hard disk space for my operating system.
Use it on older hardware.
Easily automate any task.
Create my own commands.
Configure, update and restart every aspect of my computer remotely.
Run graphical programs on my local screen from a remote connection.
Start a program running, close my connection and when I reconnect I can still interact with the same program.
Not have to worry about virus's or malware.
Not have to worry about DRM.
Update all installed programs at the same time and completely automatically.
Easily and cleanly uninstall all parts, including configuration files of programs.
Not have to reinstall my operating system because it is slowing down.
Easily transfer my personal settings to any linux computer.
Easily run my own Linux on any computer from a flash drive.
Not have to activate my operating system and give information about my computer to any company.
No more typing of product keys or worrying about losing them.
Never see a nagscreen or have a program crippled because I used it beyond the demonstation time limit.
Never have to restart the machine because a program other than the kernel requires me to.
Compile my own Linux kernel to suit my own machine.