For my wife, it's all about convenience. She's retired; I'm still working until August, 2011. We pay what I consider to be an astronomical amount of $$ for DirecTV: $95/month. That's the Choice Plus with HD and DVR service, and 3 STB's, 2 of which are DVR's. And the DVR Home thing that let's my wife watch any recorded show on either DVR. For her, she presses one button on the Logitech remote and all the equipment comes on. Another button and she sees the list of recorded shows. Another one and she can watch stuff. And, she can change channels so she can watch HGTV, FoodTV, QVC, DIY, etc.
I have Netflix and Hulu Plus, and for me it's no problem to do a combination of OTA and online streaming, especially since one of my DirecTV DVR's has an OTA antenna AND my TiVo in the basement is an old Series 2 with a lifetime subscription, so I'd have 2 DVR's to do OTA stuff with. But my wife just simply can't deal. She needs the simplicity of DirecTV with channel guide and list of DVR'ed shows to pick from.
What I'm hoping for is that online streaming will settle down and by the time I retire in 9 months I'll be able to ditch DirecTV and go for some combination of OTA and online streaming, with a STB that will do Netflix, Hulu Plus, and whatever else comes along. I guess we'll see!