I"m not sure if HDCP would affect me. We don't have any movie channels or pay per view channels enabled. Just over the air stuff, and the basic cable channels like cnn, espn, ... , and as mentioned, I rarely do this, maybe 2 or 3 times a year if there's something interesting that I want to archive on my computer. I had the impression that copy protected stuff wouldn't go out the 1394 interface of a DVR, which is what I've been using so far without any issues. Apparently HDCP this doesn't affect component capture, which would probably be good enough for the rare times I'd do this.
The only reason for switching to a new DVR is if there turns out we would want to record more than 2 channels at the same time, which sometimes happens because some program doesn't on the hour but a minute or two afterwards.
update - turns out that switching to the dvr would increase our cox cable bill by $25 / month so we won't be switching for now, but at least I'm aware of the HDCP issues. Thanks for the reply.