How exactly is Linux different from Windows ?

Like most kids of my age, the first computer I was introduced to ran the Windows operating system.

Then, by the time I entered college, I got to know of Linux. Specifically, Ubuntu - one of the many Linux "distributions". 

While this introduced me to a whole new world of fancy names and commands,  I have increasingly felt that whatever I do it Linux can also be done in Windows, and also just as easily. That is for me Linux has been just another operating system. So I wonder - Why the buzz about it ? Agreed that, unlike Windows, I can legally use it without paying a penny. More than that, is there any "technical" difference ?

My plan is to explore this along with my friend - Arun - this summer. I want to get a clearer picture of what Linux and Windows is all about !!

I realize that there are many who are confused like me. Quite frankly, the confusion is partly because there is so much of diversity in the open source world as opposed to Windows. To give a flavour, till Richard Stallman visited my college and talked about how the familiar Linux is actually "GNU/Linux" I was contended with calling anything other than Windows as Linux ! According to him in the "gnoo slash linux" system, its only the "kernel" that Mr. Linus Torvalds contributed and the rest is from GNU. 

See, suddenly I am having to contest with so much of historical background and technical details ! The open source world is indeed complicated to understand. (By the way, "open source" and "free software" are technically different. Please ask Mr. Stallman for more details.)