How many revisions or upgrades has Microsoft's "Vista" gone through?

Answer 1

Good question, but a very broad one.

Are we talking, say Development release, Beta release, Release Candidates, or versions retailers and governments could buy?

There will also be an edition available only in other countries that cannot afford Vista.

The editions that Microsoft advertises are (retail):

Home Basic
Home Premium
Business
Enterprise
Ultimate

Then there are the Full and Upgrade versions. And if you're a school, government, etc, there are Volume Licensing packs.

For this and more editions of Vista, as well as archives for at least the BETAs of Vista back in the past, this site is good:
http://www.winsupersite.com/showcase/winvista_editions.asp

Just to let you know, alot of security features from the BETAs didn't make it into the final releases. For example, Windows File system. And Microsoft was going to try to check your license keys for any program to see if you had pirated software. I think this was gonna affect MP3 files too, but that site mentions it.

Answer 2

more than you can count, with more to come... XP as been out 7yrs, and they're still updating that... now they are stopping supporting xp, and forcing users to move to vista, from next year,,, your guess is as good as microsofts.. you/they will never know.