I'm upgrading from a Series 2 to an HD DVR, because Comcast is converting many on my stations to digital-only. I don't have an HDTV, so I don't really care about the HD part of the DVR. The reason I bought the HD DVR was so that I could use cable cards and bypass a cable box. My Series 2 was rated as "180 hours". The HD DVR is rated as "20 hours HD" and "180 hours ?regular?". For my Series 2, we've settled into a "routine" where we know how many shows we can tape with the various quality levels - Best, High, Medium, ... - such that we always have enough disk space. So am I going to be in for an "un-pleasant" surprise: (1) because the HD DVR will store HD recordings in a way that takes up much more disk space than it did on my Series 2 (even if I can't watch them in HD)? (2) When Comcast switches many of the stations to digital, suddenly recordings from these stations will take up much more disk space? How does the recording of an HD program compare (in terms of disk space) to the recording of a program using Best, High, Medium? How does the recording of a digital program compare (in terms of disk space) to the recording of a program using Best, High, Medium?