Very true, but battery tech as it stands lags really hard behind the rest of the innovation that's happening with phones for a number of reasons. You're not going to find a phone today that has capabilities like this that can be used heavily for a long period of time on a battery as small as the one that comes in the D2G. Apple kindasorta gets around this by limiting what you can do with the phone (even so, I never saw more than 12 hours out of my iPhone3G's battery). Android leaves it up to you as to how you want to manage it. If you really want to use the hell out of it for hours on end with a ton of widgets, streaming video and push on all the time, you're either going to need a bandolier of extra batteries or plan your day based on where you have access to AC outlets.
My phone is actually a corporate phone, so I do need push email when I'm out. I had it on all day yesterday and it only knocked off about 6 hours off my battery (bringing it down to ~24). My strategy - until there's some huge technological breakthrough - is to fully maximize the battery life at the expense of convenience (but not at the expense of basic functionality), and the turn things on as I need them and weigh how much they're worth to me vs how much power they consume. So far it's working well and I don't feel anxious about constantly monitoring my battery level. It's all about cost/benefit.
I would love to get better battery life out of the D2G so I can use it every day.