Yes, absolutely. Using Linux will help you learn more about how computers -- specifically operating systems -- work. For instance, there are differences in how the Linux desktops behave that will point out decisions that the Microsoft developers used that you have probably never thought about.
I have been using Linux as my main desktop for 15 years. I am not a programmer, just a guy who needs to get stuff done. It has not always been easy, but it has been educational.
Today's distros are much prettier and more refined than the old days. I find myself dropping into the command line only when I want to. I can do nearly everything through the graphical interface. The command line is often faster and easier if you know the commands, but not really necessary.
Your distro choices are good ones, but expect to try others until you find the right mix of features and design decisions for you. I started with Red Hat, then Fedora and SUSe and Mint. I have settled on Ubuntu because I happen to like the Unity desktop. (That makes one of us)
Any one of the several ways to deploy that people have suggested (dual boot, hard drive switch out, separate computer) will work for you. I dual booted for years with no problems, but eventually abandoned it because I did not use it (Windows) much. Until about a year ago, I ran VirtualBox with a Windows XP client inside Linux. That way I could access Windows when I needed it without leaving Linux. But that's an intermediate technique to try after you get everything else working.
The biggest problem with going all-Linux is the assumption by other people that you have Windows and can therefore open anything they send you. Usually you can, but there are a few things that I have had trouble with. Depending on what you need to do, there is usually a way to work around it.
Good luck and have fun.