Microsoft may be the behemoth monster 800-pound gorilla of software, whose Windows and Office products are nothing short of Golden Gooses. Or Geese. Or whatever.

But it’s interesting to hear how its leaders view themselves. To hear Chief Executive Steve Ballmer talk about Microsoft, you might think it is still the underdog startup it was 33 years ago when Bill Gates and Paul Allen started the company . Or the sapling it was when Ballmer joined in 1980.

People are underestimating Microsoft. Yes, we make mistakes, but we come back and learn from those things.

His comments were made during an event today to mark Gates’ stepping down from day-to-day operations.

Can you blame them? Someone once said that as we grow old, we never lose the sensibilities of our youth: the awkward nerd may always be raring to fight the big bully. Maybe that’s why Ballmer, after some 28 years at Microsoft, said this about IBM:

We went toe-to-toe with the biggest, most powerful computer company in the world and we beat them. Windows vs. OS2.

Sure enough, the David vs. Goliath story came out with the right ending. 

And they showed (again) a funny “farewell” video about Gates, the world’s third-richest man, warming up for a “fight”, with the help of buff actor Matthew McConaughey, who while steadying a heavy boxing bag for a sparring Gates, said:

“Steve Jobs! (Jab); Larry Ellison! (punch); Nice, a head shot.”

Maybe someday that little Microsoft will be a contender…

(Here is an earlier version of the video, first shown at the Consumer Electronics Show in January, without the boxing reference, from MSN)