" I guess does anyone know the type of HD that go into Tivo and other DVR? "
At first the engineers ruled that such must last many many years and the noise level be kept down. During those times you would find 4200 RPM drives since the failure rates are very low and the lower RPM helped in noise reduction.
Today they seem to just go with lower bidder.
I am trying to build a media center pc. What are the most reliable HD to use in these types of machines. I guess does anyone know the type of HD that go into Tivo and other DVR? Thanks