WMC center is long in the tooth. Mediaportal seemed promising but getting the TV guide to work is so maddening I gave up. Is nobody really using HTPC's? Am I resigned to pay for cable or satellite?
Nope! There are more of us using HTPCs than ever before. We're just not using WMC.
XBMC Clients, MythTV Linux Server, and whatever tuner you want(HDHR is the easiest)
Problem solved.
Bingo. For OTA usage, MythTV works great as the frontend too (instead of XBMC), and MythWeb is fantastic for general scheduling, program browsing, etc, from your tablet.
The key to all this software is the guide data. Where does non-WMC get this data from?
MythTV can work "without" guide data, using the free EIT data that is broadcast as part of the OTA data streams. The scheduler can't see as far into the future using EIT as it could with purchased guide data, so it can't make quite as efficient of scheduling decisions (such as deferring a recording to mitigate a conflict), but otherwise it works pretty well unless your local stations don't broadcast accurate data. I ran an OTA DVR for ~6 months without an internet connection at all, using EIT data exclusively for the program scheduling.
http://www.mythtv.org/wiki/EIT
Otherwise, Schedules Direct is fantastic for purchased guide data.
http://www.schedulesdirect.org/