Most "open source" software is not "free," and the more time someone spends trying to define "freedom," the less free the damn thing actually is.
I'm generally skeptical of the "open source" movement. On one hand, I recognize that a lot of people get value out of open source software for private and commercial reasons. On the other, I tend to find that the underlying motivations driving many (if not most) proponents of open source are suspect at best.
I've said to Orphan before that, if you looked at any successful or "good" piece of open source software, you'd almost be guaranteed to find commercial investment behind it, either in the form of direct funding or the use of paid development / quality assurance time. This statement was mostly offhand, without any significant research to back it. That said, however, I think that the declaration largely stands. OpenOffice, Firefox (insomuch as you can consider that "quality" anymore), Eclipse, and so forth. Name a widely used or quality piece of software and I can almost guarantee that I'll find commercialism is responsible for putting it where it is today.
That's not to say that commercial software is inherently better, though I do find this to generally be the case. "Open source" includes every piss-poor project that every moron threw together over a weekend and stamped as being "open." Obviously this is going to mean that, with a much wider range of available crappy software, open source is going to look worse for it. There are, of course, many such horrible commercial products, many of which I've used. The difference is that the "community" (you may note I'm overly fond of quotation marks) doesn't automatically back and go to the defense of poor commercial software, yet they seem quite willing to go to bat for anything where you can download the source code.
Source code available or not, a turd is a turd is a turd.
My problem with open source really comes down to the users and developers themselves. To be blunt, I find the movement ultimately altruistic, and I use that word with all of the condemnation it entails (if it has no such connotation for you then, by all means, fuck off).
Three letters: GNU.
Aside from the fantastically idiotic use of acronyms by these people ("GNU's Not Unix?" That's "clever," is it?), these and many other open software groups constantly advocate open source as being "free." The slogan I hear most often is "free as in freedom," as opposed to "free as in beer." Do yourself a favor: go read look up the license terms for the LGPL (the license GNU eventually had to come up with when they realized that nobody valuing hygiene was going to use the GPL), and pay particular attention to Stallman's pleas and "reasons" (if you can consider such emotional nonsense to even remotely resemble rationality) as to why you should use the GPL instead of the LGPL. That's "free," is it?
Most people I'd consider sane (it's not an objective evaluation; you automatically fail if I disagree with you) are already familiar with this and the problems therein. But what I love in particular, and what I'm rambling on mostly pointlessly to address, is the idea that the GPL, LGPL, and all of the bastard variations thereof, do not in any sense represent freedom.
A license that restricts the usage of software to non-commercial applications is not promoting "freedom"; it's promoting anti-commercialism, and you'd have to be a child to think otherwise. You cannot claim that something is free if it places a requirement on another person (full stop), be it the requirement that the license is redistributed or maintained or that the product can only be used a certain way.
If you want to claim that software is free, you must place it in its entirety with no protection, copyright or license into the public domain. You will never see the "open source" community do this. You won't see me do it, either.