I've been commuting on a Giant Lite for the last two months. I have the same bike rigged with a hitch for an Adams Trail-a-Bike to take my six-year-old to t-ball or the library. I have a second hitch for a trailer to carry 6 bags of groceries.
With the commuting, the grocery hauling and the kid-toting, I've almost completely stopped using my car. I'm not as cool as the guys and gals in lycra and spiffy road bikes, but I'm plugging along consistently. The electric assist makes it much easier to use this bike for all the daily chores without doing a lot of prep or building myself into a Lance Armstrong level cyclist. For me, the question has flipped from "Why should I take my bike?" to "Why *shouldn't* I take my bike?"
I meet lots of other 40-something types who are pretty interested in having just enough help to make cycling fun again. If I had a dollar for every question I've answered, I'd have already paid off this contraption.
I think a well-designed and integrated electric assist would sell very well if they could bring it in for $500-700. Every nickel more at the gas pump makes this option even better.
Oh, and as a bonus, I've lost about 10 pounds and am in much better shape than I was a few months ago. It's an electric assist, but I still do a lot of work on this thing.