Short answer: 1 charge per day, take it off the charger and I'm usually around 50% when it's time to turn in. The only thing I manually change is screen brightness and bluetooth. Everything else is turned on (with the wifi sleep policy to never).
I get in excess of 18 hrs, "usually".
I had to make a few phone calls this morning straight from the charger. Had to look up tech support numbers via the phone, etc. Conference with a few ppl and get work started due to a service failure, that of course showed up immediately on my phone via the email push (love k-9 mail). I was working on the problem and getting it resolved before the customer was even open.
After that I checked a few news stories, and replied to two emails, (status updates on the outage).
So 20 minutes of phone calls, with some internet usage, emails.. and later the gtalk notification message that service had been restored..... 5 hours off the charger, and my battery is still reading 90%.
Yesterday I barely used the phone at all... except for some remotedroid action watching hulu and netflix on my laptop. Some minor internet (reading local news feeds...) I think it was 14 or 15 hours off the charger.. and when I popped it on... my battery was @ 80%.
Google measures usage as 10 min per hour. It should last all day + without needing to be charged.
The phone from a 100% charged condition should last 3-4 hours while streaming youtube HQ content. (max load on cpu, screen, and multiple radios).
Usage patterns are subjective, in that, what we describe as light, moderate and heavy, may not equate to your expectations of what those terms should mean.
crankerchick mentioned "spare parts", and I'll +1 this. Its an invaluable tool for determining what, or if applications are causing bad things to happen WRT your battery. Specifically the "Partial wake usage" <<--- this is what is waking the phone up from deep sleep. If there is anything above "Android System" in the list that you don't expect, kill or uninstall that application and see if that greatly increases your battery life.
Signal quality also plays a major roll in standby time. Crappy signal means more power to transmit = less battery life.
But if the phone isn't making it a full day without needing to be charged.... then something is wrong. And the worst thing you can do.. is "I'll try to live with it..." ... get something that works, that you won't resent paying for
