I just hope they dont discontinue guide data. As long as they dont do that, I dont see any reason existing hardware/setups won't be good untill win 7 support reaches end of life many years from now, which should be plenty of time for people to get their money's worth out of what they have invested in their setups, and hopefully a suitable alternative being released in the mean time weather it somehow someway be existing alternatives that dont have good if any cable support like Myth, XBMC, etc, or something entirely new. I dont see any reason for them to otherwise kill off WMC functionality in other ways in the mean time. Guide data is key to the whole thing working on the cablecard television side, and there is wording right from the beginning that says they can stop providing that at any time, so that will be the wild card. If they did happen to kill off the guide data, I often wonder how deeply entrenched in the coding that is to overall operation, as in if it's not too deeply integrated if some workaround using other web based tv listings such as google or yahoo could be used in it's place.
Basicly while certainly not good news, and making the future of such setups anyones guess, I dont see putting together a new WMC setup today as being a waste of time or DOA. Despite WMC not having much if any of a future, one should still be able to get years of use at the current state...barring they dont pull guide data or no good workaround surfaces eventually if they do.