I vote for Vista, because I've had it for 2 years and it's been running flawlessly-- no crashes, no fatal errors, not one virus. I like it because it looks great, and a lot of the programs I run are Windows-only.
Linux is great too, I use it occasionally, but I prefer Vista over it because of the compatibility of it. Even though Linux has its own version of pretty much any application, I still prefer Vista because I got my laptop for free, and that includes Vista. Vista looks good and runs smooth. Also, it's very customizable.
As for Macs... I'm just gonna be honest. I will never buy a Mac or any Apple product anymore, because their sales techniques are just down right low. Their advertisements are so gutless. They have a person from Apple acting as a person from Microsoft, that talks about all the flaws Vista has, most of which are made up. For example, in those commercials, the Mac guy is always bragging about how he can make movies and such on his Mac, and that's why it's better than Vista. The truth is, Vista DOES have a video editing program that works great. As for the no virus on a Mac concept, the reason behind that is because hackers know that people with Macs don't have information important enough to be worth hacking, and not nearly as many people use Macs compared to Windows, so why would a hacker focus on hacking the minority of people when he can get the majority of people?
I mean the list goes on when it comes to all the dirty tactics Apple uses. For example, they have an internet ad of a 1990 Macintosh comptuer and a new laptop running Vista. They start both computers, and of course, the Mac is fully booted. They try to make it seem like 1990 Apple technology is superior to Vista. What they fail to understand is that Vista is far superior to Mac, therefore it naturally would take a little longer to load. It's like comparing the start up time of a Super Nintendo Entertainment System (SNES) to the start up time of a Sony Playstation 3 or Microsoft X-Box 360. Both the PS3 and 360 are at least 100x better than the SNES, but they start up slower than the SNES because they have tons of graphics to load.
Anyways, sorry for the ridiculously long rant, but I hope I get best answer lol. Have a good day.
PS: Oh, another reason why I don't like Apple is because Mac users, for some unknown reason feel obliged to brag to EVERYONE about how great their Mac is, when really, the difference between Mac and Vista is the graphical interface and applications, so it's just a matter of preference. Macs don't have some secret technology, they run off the same technology as PCs do. They're much more expensive too.