In order to record two channels (view one channel, then record the other) the DVR must support two inputs from your satellite, cable or other provider. Unlike the old analog signals, digital signals cannot be "split" so you must provide for two separate inputs. Your television doesn't really play into the picture as it will be handling the signal it is being fed and is not worried about recording.

In a nutshell, when purchasing a DVR recorder make sure it supports more than one input and provides more than one output (for multiple devices). Or, to reduce your clutter, consider getting a DVR directly from your cable or satellite provider which already has this functionality built in.