I guess I won't be updating to Windows 8 if Media Center is mostly the same anyway and I'd have to pay extra for it... But something tells me there will be added functionality of some kind that would make me consider the upgrade (slicker GUI? amazon instant streaming plugin?)
But overall, I'm more than happy to stick with Windows 7 Media Center, along with the plugins I have installed:
I have found myTV (http://mytv.senseitweb.com/
) and My Movies (http://www.mymovies.dk
) to be the best for organizing my TV and Movie libraries, respectively. MyTV has a service in that runs in the background so when an RSS feed picks up a new show and puts it in the right directory, the myTV service will look at the filename and scrape metadata for that episode of the show folder its in. Works very smoothly. Wake up the next morning, go to the myTV strip in Media Center, go to the new episodes button, and all the shows your RSS feeds picked up will be ready to watch, already organized with metadata scraped. MyMovies, in my experience, requires more of a hands-on approach to add movies to your collection database, but for what you get out of the plugin, it's not so tedious.
The defunct Advent's Media Center Studio software is no longer distributed by them (their website is gone I think) but you can find downloads for it around the web, though setup can be a pain. Media Center Studio allows you to rename or remove unwanted buttons, or add buttons to different strips or remove them altogether. It also allows customization of the background and fonts in Media Center with theme files that can also be found online.
If you hate how a maximized Media Center window doesn't let the mouse leave the media center window, then a plugin called The Maxifier (http://www.mods.com.au/Maxifier/
) to be very useful. This way I can browse the web on the small computer monitor while media center is running full screen on the plasma. This plugin also lets you create keyboard shortcuts for maximizing options, which I was able to tie to my Media Center remote control using EventGhost.
The other plugin that I really appreciate is http://www.mychannellogos.com
which adds channel logos to the TV Guide screen and allows some other customization of the guide screen than can help improve its efficiency.
I don't use anything else (Music, Pictures, etc.) in Media Center so I use Advent's Media Center Studio to remove all unwanted strips and buttons in the Media Center start menu, and added the Netflix button to the My Movies strip. So now Media Center starts with a nice customized background, and one strip of buttons for my movie library/netflix, one strip of buttons for my tv library, and one strip of buttons for Live and Recorded TV. Very clean interface.
I suspect I'll be using this combination of plugins for a long, long time until I can no longer use the plugins for whatever reason. I admit that new silk smooth interfaces is tempting. But no other media center alternative has such a simple interface (though I went through great pains to find the plugins and get them working) for keeping track of a tv show library, adding movies and keeping track of a movie collection, and live tv with dvr functions. So for me, I'll probably be using Windows 7 Media Center for a long, long time. I'm hoping in the future something like Kinect or Leap (leapmotion.com) will allow an even more fluid and seamless interface with which to manipulate Media Center. But for now, with my 3 siple strips in the Media Center start menu, using a remote control works well. I see myself using it for quite a long time.