It's great to see the number of responses to this thread, and with the talk of multiple projects for this feature I feel a whole lot of progress could be made over the next few months. TV heaven beckons (heaven = no real estate investment reality programmes & no life invading advertisements).
@Gamester17 I've signed up for integrating libnemesi into dvdplayer, and have started work. Assuming no natural disasters occur, I will make the SoC deadline.
@elupus & jmarshall : Producing a cross platform/application frontend certainly seems more pertinent to me. I'm very happy to hear of developers with this in mind.
@Nick8888 I'm of the opinion that a separate TV section would be the most logical route to take too. For the sake of completeness you could always have "TV Recordings" available as a built in source in the videos section.
Thinking aloud while looking at your diagram I see some improvements that could be made. Because of the way many people use televisions a more immediate link to the TV guide and live TV might appease many non-geeks like ourselves. The option to flick at will and pull up the EPG easily would suit many people (excepting myself).
I think the schedule conflicts could be integrated into the EPG for simplicity.
I'm not so keen on merging the PVR facilities with ripped TV series, this might blur the distinction between the two. What could be handy is automatic inclusion in the video library, once you hit "series record" in the EPG/OSD.
I have a few other ideas on the GUI aspects and so perhaps it's a good idea to create a wiki page as a resource site for this sort of discussion.