I'm not even certain if Microsoft cares anymore. Perhaps this really is a good thing for PC gaming, as it will either force Microsoft to put more effort into the platform, or it will introduce new choices to users as a result of Microsoft's apathy.

I thought G4WL with Games on Demand service w/ their recent sales for SF4 PC and Batman AA PC was a smart move for them...
...but what Steam might be doing now might just put the nail in their coffin, if Microsoft don't shape up.

Games for Windows is something Microsoft should have implemented years ago. Their me-too LIVE service should have been introduced in 2005 alongside the 360. Whatever happened to cross-platform competition and special deals with PC makers to offer affordable pre-built gaming PCs?
So much potential has remained unrealized.

Yeah, it's true. Valve has posted a statement, which is also available at gaming news sites.
As for what games will be available, outside of Valve's titles, no information is available.

Valve is most likely lining up agreements right now. While their own games are great it would be a bit silly to launch the Mac OS store with all of ten games. ;)
A lot of major releases have had Mac OS ports--either simultaneously or a few years later--so Steam could potentially have quite a catalogue, although bear in mind that the majority of those are the Windows version running through a wrapper rather than using native code, and in some cases this has resulted in the game running much worse than the original Windows version would on the same hardware.

melchiz, I am saying only this in regards to your freedom being stolen away by Steam: go shop somewhere else! There aren't that many Steam exclusives and if you want a game that's exclusive to Steam then vote with your wallet and don't buy it. You have the freedom to chose from where to buy the game, Steam is not stealing this away from you. For some of us the value added by Steam is high enough to be worth the things we're giving up, and I for one value convenience a hell lot more than having the option to play the game without Steam running in the background.
I for one doubt that you will be able to chose OpenGL on Windows and let me tell you why: OpenGL relies on a lot of custom vendor extensions to accomplish things that DirectX does natively; the problem with those extensions is that they're so crappy of an implementation that a hardware vendor might chose to not support an extension on their next revision of the hardware (think nVidia releasing a new video card that doesn't support an extension that the previous generation did or an extension is deprecated and the company forgets to write a wrapper) and then it goes into software rendering which kills any trace of performance. This is sort-of-OK on the Mac platform where the number of available cards is small but not so well in Windows-land where the variety is so much greater.
Another problem with OpenGL in general is that you never know for sure when it will switch to software mode and for what reason and this is inherently bad. Another one would be that it isn't a forward looking model like DirectX (DirectX 11 comes out before cards that support it do and that sets a standard spec for hardware manufacturers to follow).
All of this of course depends on the way Valve will choose to implement OpenGL in their games and what extensions they choose to use.
If you're interested you can read a much more detailed discussion about DirectX vs OpenGL here.

I do avoid Steam. Sadly, more and more titles are forcing Steam on users (Dawn of War II, Just Cause 2, Modern Warfare 2, and so on), so I consider Steamworks an affront to the freedom of PC gaming.

I really don't understand that sentiment. How is Steamworks really any worse than games that already have built-in updaters and multiplayer match makers or use other things like Gamespy exclusively for multiplayer/online components? At the same time, you said earlier that GFWL was not a bad thing at all when it is essentially the same exact thing as Steamworks, only its not part of the Steam platform. It just seems like an irrational "anti-fanboy" response to Steam, i.e. it is associated with Steam, therefore it must be bad. It's really just as bad as all those Steam fanboys who think that Valve and Steam can do no wrong.
If you look at the platform objectively, it does have both positives and negatives to it, just like any other system. On the negative side, we have the need to run the client just to play the game, the integration of the store (which is arguably very anti-competitive) and the need for a constant internet connection (never mind that you can run it in offline mode, people still seem to count internet connectivity as a negative). On the plus side, we have an excellent download manager and game organizer, community integration, multiplayer matching. On the third side of this (did I mention this is a triangular problem?), we have those features that seem to divide people, like automatic patching of games and for some people the idea of the "Steam Cloud" (and could computing in general) is horrifying, for others, it is a godsend. Taken together and weighing the pros and cons of each I can see how some people might not want certain features of each aspect of Steam, but I fail to see how anyone can consider it as a whole bad or an "affront to the freedom of PC gaming".

I guess his problem is that more developers are finding that using Steam as an exclusive way of distributing their game is worth it and chose to make their titles available only on Steam (or via Steam tie-in).
The whole issue comes from the fact that DEVELOPERS are choosing Steam as a distribution platform and not Steam forcing the developers to use it. This is the reason I don't personally understand his constant flaming against Steam

Well because Steamworks using games also come with Steam online activation DRM while GameSpy and GFWL let you play sinple player mode without needing online activation. That's, for me at least, a huge difference.
I wouldn't mind Steamwork at all if it was only used for "community" stuff and multiplayer.

Yet again, why not write angry letters to the developers or just don't buy the game and instead blame Steam for all the evil in the world?
Do any of you seriously think that if Steam wasn't developed another service doing the same thing wouldn't of taken its place?

Why do you find it so difficult to comprehend that some people do not want to use Steam?
Here is a simple example: A user wants to play Dawn of War II. That user doesn't like Steam. He can either avoid the game or swallow an unpleasant reality and let the game install and run Steam every time he wishes to play. Both choices leave the user dissatisfied.
"Fanboy"
"Flame"
Whatever.
I think it is perfectly reasonable to not want to run Steam. I want to play some games, but I do not have a choice, because Valve seduces developers with its Steamworks package, which conveniently requires the Steam client (complete with its storefront and advertisements) in order to function.

Precisely. If Steam had a "Steam light edition" for Steamworks titles, I would be far more accepting of the service. To me, Steamworks is nothing more than a brilliant ploy to lock more users into the Steam platform.

I find that quote brilliant. Valve seduces developers with its Steamworks package? Seriously? How about developers see benefits in using Steam over another implementation (be it one created by themselves)?
I seriously doubt a publisher would choose Steam if it didn't have a solid business case built behind it that makes the whole deal profitable (be it financially or any other way) to them.

I have written several snail mail letters (professional and rational in tone) to publishers that have used Steamworks, including THQ and Square-Enix. I calmly explain my objections to the service and inform them that I will not purchase any titles that use Steamworks.
But alas, I am a mindless anti-Steam fanboy, or something. I suppose that my refusal to do business with certain telcos is some sort of misinformed fanboyism as well, yes? Must any outspoken objection to a popular entity be met with such labels?

Why publishers (and developers) love Steamworks:
1) It is free
2) It prevents re-sale
3) It is well-loved DRM (as opposed to much-hated DRM, such as SecuROM)
The auto-patching and community features are secondary to the above.