Hmmm. . my Mitsubisi LT-46231 has an 8-Day program guide and I use it all the time to time shift our HD TV programs we like to watch. It also allows output , albeit 480i, to record programs to an external DVD recorder or S-VHS recorder from live TV or from our (IEEE1394 Firewire) DVR. One reason I bought the Mits in 2007 was BECAUSE it had so many input/output options, including two IEEE 1394 Firewire I/O ports. The I/O panel is huge and TV makers have only reduced I/O capabilities a great deal in the last few years.
And Panasonic has TVGOS on the OTHER devices such as the DHG-HDD250/500 recorders.
Otherwise, of course, there is always the option of using a home theater PC with a tuner card or online streaming to record video and store it on a hard drive. There are many possibilities these days to record OTA, cable, or web based streaming programs of all sorts. In fact, it gets almost confusing with all the overlap and options available.
I've resorted also to viewing past episodes of TV series on our HTPC, but to me it defeats the purpose of having an HDTV somewhat since the video quality it not as pristine as OTA reception. So, yeah, lot's of options, but also trade offs too.