According to this report Media Centers are gaining in popularity. I bought one myself a week ago and I'm very happy with it. I was looking at purchasing a new desktop, mainly for work-related activities, and for my wife to edit her digital pictures. As I kept thinking about it I realized that I wanted a media center. A few of my colleagues have one and they rave about them quite a bit. Plus my TIVO can only store about 35 hrs worth of TV and there's constantly at least half of that taken up by Highway to Heaven episodes (I can't get enough of it... don't ask). I'm planning a 4 week trip for later this year and given all the shows I like to watch there's no way that a month worth of entertainment is going to fit.
My original plan was to have a local shop build me a customized rig when I stumbled upon a fancy HP Media Center with a 21" widescreen LCD monitor at some well known warehouse store. Resistance was futile... I bought it and ended up spending twice my original budget. First time ever that I buy a name-brand desktop. Anyway, it's working great. Last night I installed the Windows Media Center Extender on my XBox and for the first time in years I was able to watch shows from my home country on my television set. TV recording is the next step. If it's as easy to setup as the rest was, we'll be up and running in no time!
I've heard more than a few people complain about the lack of innovation in the PC space in the last few years. Maybe the reason why Windows Media Centers are so popular is because they open up such a brand new set of possibilities. If you're already living the "digital lifestyle" a Media Center is a must-buy.