That's a little disingenuous in your price estimates. In the case of Michael Dell, he's going to be using his companies corporate site licensing for Windows and Office. Which per seat would cost a lot less than your estimates there.
Also, as they're Dell he's getting his PC at cost.
So for him this would cost substantially less.
Now, for the rest of us?
If you have three PC's in your house pick up the family pack license when it releases, that's 3 copies of home premium for $150 ($50 per PC), Or you can get the OEM system builders edition of home premium for $89 I believe. (Recent Fry's ad)
Have any college age student in your house, have them buy your Office at the Student price. (Which could also work for Windows to lower the cost)
As for the hardware, if you are actually buying a full built system chances are it's going to come with the OS on it, so you can remove the seperate OS cost.
If you're system building for yourself and are that budget conscious you can get a i5 quad core and still see most of the benefits. (As the first review of the Nehalem process you linked said :
"Basically, if you already own a Quad Core Q6600 or a higher end Dual Core CPU, upgrading to this won't improve your performance by a great degree."
In your pricing estimates you're ignoring the first rule of shopping. Never Pay Retail.