I'm finding more and more nonsense about this release, this stuff from the Bungie.net forums.

Check this guy out:

Unless you get a Gold Windows Live account, you're basically playing a demo of Halo 2. Microsoft wants you to pay for stuff that is free in virtually every other PC FPS.

Wrong, there's just so much wrong with this statement. Firstly, what on Earth is a Gold Windows Live account? There's no such thing. OK let's throw the facts out:

1) You can play Halo 2 online for free, you get a typical PC-style server browser.
2) Those who have an Xbox Live Gold account, get matchmaking features like TrueSkill (or whatever its called) and can earn multiplayer achievements.
3) I wouldn't call being able to play the whole single player without an Xbox Live Gold account a demo, you don't even need a silver account.

If you buy Halo 2 Vista, you're supporting this blatant rip-off that Microsoft is trying to pull. If Windows Live becomes popular, in the future, a lot of games might be like Halo 2 Vista.

What's Windows Live got to do with Halo 2? Windows Live is a rehashed semi-rebranding of MSN. Games for Windows is unrelated, and is really just a logo program for games, like Certified for Windows logos etc.

A lot of games might be like Halo 2 Vista? Great, I want to earn achievements in PC games, and be able to voice chat with people on their Xboxes. I've got an Xbox Live Gold account, I won't say no to some extra features for PC games.

The only reason Halo 2 Vista is Vista exclusive is to promote Vista. There is absolutely no reason why Halo 2 couldn't be done on XP.

Sure Halo 2 could be done on Windows XP. But it wouldn't have all the Live features, which are only for Windows Vista. Microsoft don't need a little game to promote Windows Vista, which is selling twice as fast as any previous Windows release, and in only five weeks eclipsed the entire Macintosh platform. Microsoft made a business decision to only release on Windows Vista so they could use Halo 2 to show off some of their new technologies.

My point is that Microsoft wants you to pay for stuff when it's free in other games

Other PC games don't have the fancy Xbox matchmaking thing nor achievements, so you are wrong. Halo 2 has the standard PC multiplayer stuff for free.