Usage: 8 Hours, 1 Minute
Standby: 3 Days, 10 Hours
Remaining battery: 1%
Brightness: 30-35%
Mobile data: always on
3G: only activated when needed (picture albums, maps, etc)
Location services: always on
Notifications: always on
Mail: manual (prefer not to be notified till I check)
WiFi: only when home
Usage: About one hour of music. Remaining usage was between gaming, surfing, FB, Twitter (picture uploads), photo-taking, maps (for travel routing with GPS on), instant messaging, reading (ebook, RSS; about 1.5 hours total), remote control, alarms, etc.
During this period, I saw that push notifications use very little amount of battery. Generally, I also find that the iPhone 4 battery does not drain when in standby (locked). I have been waking up to find the battery percentage to be the same as when I went to sleep (about 7-8 hours). Settings are as above, but with WiFI turned on instead of 3G.
Skype users: Be sure Skype is not running in the multitask bar unless you really need it to be (version 2.1.1 as of writing). It easily depletes the battery by 15% over 7-8 hours of standby. During a 4-hour Skype call, the battery was down by 30-40%. The usage drain is fairly reasonable, I think, but the multitask drain is not. During the days when I had left Skype in the multitask bar, I thought I had a bad battery. Hope Skype fixes this soon. For now, I stay on IM (push notification), and then moving over to Skype if needed.
If you have closed all apps in the multitask bar and the battery is draining in standby (locked), you should try powering down the phone (without holding down the home button) and powering it back up again. This always helps my iPhone to get back to ultra-efficient standby.
I also find that toggling between WiFi and 3G goes a long way. WiFi enabled when home, and 3G enabled only when I need the speed while on the move.
Just doing this battery run for curiosity. From now, I'll be charging it when the battery hits red, and also, a full cycle recharge once a month. Don't think I want to worry about the battery too much too. My own 'strategy': just use it with no worry till it hits red — then, turn 3G off, empty the multitask bar (maybe even power on/off), and it should keep me happy with music for the trip home.
Lastly, I think standby time is meaningless. You can practically keep the iPhone on standby for days and days before you start running it down from more than 90% to nothing for many hours. Or more commonly, you may use it for about 2 hours on the first day, and let it be on standby for 7-8 hours (when you sleep) without it losing any battery at all, and then another 2 hours of usage the next day, and may let it be on standby for another 12 hours, and so on.