Which is why I use Vista (soon to be Windows 7) MCE. Linux is only free if you place no value on your time.
I agree, unless you enjoy learning new things. Then maybe its not all wasted time. I did learn a lot about serial ports and building custom kernels in getting LIRC to work, which I can see being useful information to have in my pocket someday. But for people that are content to be locked in to MS's sandbox forever, you're right, it's a waste of their time and they should not go anywhere near it.
And in my opinion Vista is an attractive option only if you place little value on your privacy or freedom, and enjoy being milked by MS for hundreds of dollars for an OS that is at best, marginally better than XP, and at worst (and in my personal experience), a bloated piece of crapware.
Philosphical arguments aside, even if I wanted to, could I throw Vista on my 5 year old computer and play 1080p content on it? I doubt it, and if it could, I would have to lay down some serious money for an OS and a software player (which still wouldn't have an interface anywhere near as cool as XBMC), and probably some other supporting software. Then if I decide to do something basic like swap hard drives or add memory, I will need to get daddy MS's permission to continue to use the OS that I paid for. Paying $200 for an OS and then getting treated like a criminal... sounds like fun. But with Linux I can play my 1080p content, with no RIAA/MPAA/MS driven restrictions on my freedom, for free. And it looks cool as hell to boot (seriously, show me an interface slicker than XBMC).