You think that blows?! You have 20% remaining after an entire day of usage, standby all night, and then half a day! That's great. What were you expecting from a 3G phone with a screen that takes up the entire front of the device?
I just don't get how people think Apple can magically make the iPhone last for 4 days with the technology that's in the iPhone. Ridiculous.
Maybe that is the problem. I've never had any kind of smart phone so my expectations were a little high.