I still remember when I got my first VCR. It allowed me the freedom to go out on a Saturday night without missing SNL. It wasn't the easiest to configure. and many chose to not even set their clock and simply use the device to watch movies. But for me, it cut the chain to linear tv watching and allowed me to not miss favorite tv shows. It freed me from having to choose.
When Tivo came into the house, it not only made it easier to record multiple shows, but even easier to locate, watch, and fast forward through commercials. No longer did I have to locate the show I wanted to watch on a tape, or keep track of multiple tapes that were constantly being re-recorded over. Tivo even recommended shows for me to watch. Heaven; even more freedom.
The DVR exists in my house as well and is used primarily for kid's programming. It's advantage for us is that it records digital programming, while my Tivo is on a set without a cable box. My kids have grown up on DVRs and on demand. They understand fast forwarding and tv programs when they want. Waiting for a show to start is foreign to them.
Does it matter that our Tivo is not yet online and connected to Amazon or Netflix. Not really. The combination of on demand and DVR provides enough choices for us so far. Where I see the challenge is when I want to watch the show on my TV but have the ability to copy the show to another device to take on the road, either for the cars dvd player or pc or ipod. If the DVR box could simplify the mobility piece, I'd be even happier.