I planning to buy an HDTV receiver to hook up to my analog rear projection tv since most of the stations in my area have started HD transmission. I'm planning to buy a used receiver/tuner using ebay. I've noticed that for about twice what I would have to pay for HD receiver I could buy a used HD DVR that comes with a built in HD receiver. Most of these HD DVR's are from satellite providers like Direct TV. I'm not planning to subscribe to any satellite provider just pull HD over the air. My question: can I use the DVR to record HD over the air...are there any potential technical problems that I need to be aware of if I do buy a DVR or am I better off just buying a HD receiver/tuner and forgetting about the DVR part of it?