>Secondly, Windows costs considerably more when you don't buy it
>pre-installed... From 99$ for XP Home (which is crap) to 399$
>for Vista Ultimate (which admittedly isn't even out yet)

Exactly. Nobody needs Vista Ultimate. If I were a Mac owner who was buying a copy of Windows just so that I could run a few choice Windows apps, I'm getting the $99 XP Home. There are number of other cheap ways to get it, for instance if she's a student and her University has a deal with Microsoft, or if she works somewhere and has access to a volume licensed copy (note: not legal).

>I'm not sure how running another OS as a virtual machine is easier
>than compiling a program from scratch in any case (and in this
>one it is unnecessary).

Are you serious? Parallels is slick. You install it, and from what I gather it's fairly intuitive to load Windows up and launch a virtual copy. Building a unix app from scratch, even with autoconf, when you're not a programmer and have maybe never dealt with a unix command line? Way harder. Especially if you have to download and build supporting libraries, like I needed to when I built tintin++ for OpenBSD.