All my HTPCs are PC & Windows 7 Ultimate. I don't have any issues that some people complain about.
I am perfectly happy with my PCs.
I see absolutely no point of spending $1,500 on some Mac when a decent PC only costs $500 after the sales.
That $1,000 that I save could go to my speakers budget. Or maybe that's room corrections or equipments to measure.
I have this really cheap $300 eMachine as a backup in my computer room. It's 7 yrs old. It has taken a beaten from my 2 daughters since they were 3 yrs old. It is still running just fine on Windows 7 Ultimate.