My gf - a sales/marketing pro - had a lot of trouble with this when she switched to iPhone; she was use to not paying much/any attention to her battery until the phone complained... She had to get use to charging every night.
It's easy to discount this but it was a pretty significant issue at least initially.
But again, we are not normal folks though I bet this isn't that unusual the more I think about it.
They started making USB wall plugs after all (which is a great idea).
http://www.engadget.com/2009/12/05/10-usb-power-outlet-leave...
I don't get the obsession with thin phones. I'd much rather have a thicker phone if it lasted 2-3 days instead of 1.
Rather than being stuck with the extra weight everywhere you go, you just incur it when you actually will be away from a charger for multiple days.