I am a non-windows person myself... but I have Windows Media Center running on a dedicated Windows 7 system sitting in a cabinet using a pair of HD Homerum network tuners as my PVR. I use the ATSC/Over the Air Ones, but you can also use the HD Homerun Prime's for cable TV, that have the CableCard support and allow you access to encrypted premium cable TV stuff.
https://www.silicondust.com/products/hdhomerun/prime/. Personally, I put in a nice TV antenna, and have access to nearly 30 channels of over the air TV for zero dollars. I literally spend ZERO/month on my TV/PVR.
I highly recommend Windows Media Center. Its probably one of the best products Microsoft ever came out with. And I only have Mac and Linux computers in my house other that that one system that runs it. It requires nothing but a copy of Windows 7 that has Windows Media Center as part of the version (Professional, HomePremium or whatever the hell they are called these days). And no monthly fees, the TV Guide data is free forever.
You can use XBOX 360's as cheap, full featured multi-room extenders with LiveTV, Recorded TV, and accessing a DVD/Movie/Video Library.
Or if you want to go even more DIY can use ServerWMC running on XBMC Client such as I have using OpenElec running on a little Raspberry Pi in the kitchen. The ServerWMC for XBMC Client works ok, but the Xbox extenders are very polished native Windows Media Center interfaces and a little more friendly. I use 2 Xbox360's and one Raspberry Pi on my network. I am not ready to get rid of the Xboxes because they are just a little easier for the family to use. In fact, in our bedroom I have the xbox to automatically go into the Windows Media Center when it is powered on, so my Wife does not have to select anything at all.
But, this setup, gives me 4 HD Live TV tuners, and all the storage I can throw at it for media storage anywhere there is a network connection the the house.
And now that the XBox One is out, its making 360's cheap to pickup as extra extenders if you want.
I also use the MediaBrowser plugin(now called Emby) for Windows Media Center which has a great library to store and watch your movies and old TV seasons you store on the system
http://emby.media/download/.And I use the mediacentermaster program to manage the library and automatically download DVD covers, backgrounds, etc..
http://www.mediacentermaster.com/wiki/index.php?title=MediaBrowserI have tried others like Myth, Sage etc.. and frankly as much as I personally dislike the Window, I have to say that Windows Media Center is by far the best option.