Our ReplayTV box is really old and has very little capacity. But, I do like their "MyReplayTV" service which lets you program your box remotely from a web interface. Here I am on vacation in Tahoe and I just set my box to record the Nascar race on Saturday. Life is good!
Update 2003-07-06: Well, MyReplayTV is reallly cool if your ReplayTV box is successfully calling their servers each night, which mine was not :(