You can run Unix applications on Vista.
I've yet to test it, and I have a nagging doubt that they've reintegrated POSIX into the kernel and X11 into the GUI - It will be under some form of mid to high level emulation or API, similar to Cygwin which allows you to run UNIX code on Windows XP, 2000, NT, Server 2003, etc already.
And after a certain threshold, what iLife provides is too limited for the advanced user to use.
And after almost any threshold, Solitaire, Notepad and Windows Movie Maker are too limited for even the home user to use which invalidates the point.
And all of the advanced applications are available to both windows and mac.
No they're not. The most popular advanced applications such as Logic and Final cut are Apple products for the Mac alone. You must be thinking of Microsoft Office and Photoshop.
And as for your point of Windows Media Centre being the equivalent of iLife? That's garbage. Flat out garbage. Windows Media Centre is at best the equivalent of Front Row - and the Media Remote is the Apple Remote. I won't contest as to which set are better, I've never tried any of them.
Reverting to your original point of emulating easily, (Like Darwine and cygwin respectively.)
Emulation does not provide the performance of native support. Not by far. You could theoretically emulate Mac OS X on PC DOS 7, but with all the various additional compatibility layers it'd be slow as hell - even on the latest hardware.
Mac OS X has the advantages over Vista that it is integrated, accelerated and fast - with excellent native peripheral support. It runs on a Stable, Open (Until 10.4.9 :/) UNIX core based around the XNU kernel, derived from Mach 3 mklinux and FreeBSD 5.
Vista has the advantage of being Windows - It's familiar to users, (A different thing from easy to use) and it has a wide range of application support.
Mac OS X has the disadvantage of being often inflexible without low level modification (Although this doesn't tend to be more than a plist) and that it does not execute imperfectly native acceleration as efficiently as Windows does. (Vista is the opposite - it's Aero system requirements are horrific because of it's code inefficiency yet games and other external applications run beautifully.)
Vista has the disadvantages of a closed system that is based on well maintained but initially unreliable code. It is not feature complete by default and its applications are piecemeal and lack standard or interconnection. It's native hardware support is not far short of abysmal and its creator and fanboys have LASER beam eyes that will Fn0rd1n9 Pwn (7M) Google
Oh, and a resource hog ? Apparently not, see:
I'm sorry - Minimum of 1GB RAM? 4200 notebook drive not enough? a 128MB graphics card just to run the full operating system? Sounds resource hog hoggity to me!
Again, to bring it back to the ol' G3: My iBook has 16MB ram. Runs Tiger Fully accelerated no trouble. Yeah. has 256MB ram too, and a 4200rpm HDD. Only the CPU is an issue, and for light work it's fine - even for DVD's etc. It's only "Heavy" processing such as DIVX decoding which cause an issue.
And as for the "Ground Up" comment, in the original design briefs and spec sheets for vista it was going to have about 10 or so major features, including an entirely new filing system that ould revolutionise the way we work with computers. I don't see it.