It is definitely worth calibrating/conditioning your battery multiple times by running it until the screen goes completely black and then recharging it to 100%. The full drawdown (and not just draining the battery to the 20% level) makes a big difference.
My 32Gb black 4s ran to 20% in two hours on the first day. So I calibrated the battery once by drawing it down to screenblack and began shutting things off and disabling/re-enabling/resetting services just as everyone in this thread has done and the battery life improved to 4 hours of use and 25 hours of standby which is still not close enough to spec for me.
So I calibrated again, and, in the process of draining the battery, manage to watch more than 45 minutes of a 720p movie with the battery indicator at 1% which suggests that the phone hasn't yet figured out what a normal current drawdown looks like. After two full calibrations, I'm not done drawing the battery down yet, but it appears initially that it will last significantly longer than the last battery cycle
Thing is, faulty battery calibration could result from either an iOS5 bug or a hardware bug or a random synergy between the two and it would also explain why not every new phone is affected as well as why not every upgraded iPhone 4 is affected. It also has explained why random battery drain has appeared as a bug for a significant number of users of past upgrade cycles.