I have a BS and MS in computer science. They got me my first job. At this point (12 years later), if I were seeking a job, the MS might give me a slim edge over an otherwise comparable candidate without one, but I don't think it's very important.

My MS actually felt a lot like a repeat of my senior year, but as near as I've been able to tell, that speaks more to the strengths of my undergraduate school than the weaknesses of my graduate school.

I think understanding the theoretical underpinnings of computer science is important, and unlike a lot of people's reports, I did a lot of practical work. (Well, practical to a point. It's not like I was solving new problems or anyone was going to be using my programs after the fact.)

And some of the best programmers I know don't have degrees but they did learn the theory and do the practice on their own.

So it's not necessary and the degree program alone won't make you a really good programmer.

But if you're going to get really good without going through that formally, you're going to recreate at least some of it on your own.