I'm a Mac user and I admit that Vista is a good operating system. Sure, it has its bugs right now, but what MS OS isn't buggy for the first 6-12 months? Vista will be fine. People said the same thing about XP when it launched. With that said, I won't be installing it for probably another year.

Try Newegg for reasonable prices.  Home Premium is $111. 

http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&DEPA=0&Description=vista

See...I'd rather pay $50 for an OS, no more...is that crazy?

Being anti-M$ as I am, I hate to say this but... Vista is pretty reliable. I feel that Vista is the best product that Microsoft has put out in a long time, reliability wise. It could give the impression that Microsoft has changed their ways, and encourage more people to buy the 360. However, when these people read into the 360 they're probably going to notice that the 360 is probably one of the most unreliable consoles ever made. However, in saying that, the mass market doesn't generally look into these things, hence why Microsoft are in the position they are in at the moment (WW domination in the software market). I'd say out of all of the people who buy consoles ever only about 25% of them will properly look into things like the reliability of the console... seeing as this should be a given. Well, that was a pretty unstructured post... hope you like it ;)

EDIT:Basically, I am saying if Vista has any effect on the 360 sales, it would be more a more positive effect on sales than any previous operating system released by microsoft.

EDIT2: Hey, what happened to my paragraphing... I lost it in the first edit.