Other features every DVR should have*: A "second airing" option in addition to "First Run" and "Repeats," for shows that air multiple times a night (i.e. every cable show). So I can record South Park one of the 400 times a week it airs without interfering with something else or recording a million reruns.

*In a previous post, I mentioned an "undo" button or recycle bin for when you accidentally delete episodes (which every single person with a DVR has done at least once), a feature that I estimated would take about ten minutes to develop and implement.