I'm in the same situation as you here. My iPhone 4S's battery dies incredibly fast especially after the 5.0.1 while my old iPhone 4 (now my GF's phone) and my first generation iPad, their battery life improved significantly with the update. So I guess is something with the 4S.
One more thing, in 5.0 I sort of fixed the battery issue reinstalling my exchange email account. I did this too after the update to 5.0.1, but opposed to the first time with no effect at all to the battery life. The location settings related to time zone, and cell tower location are deactivated, I saw these can cause battery drain too but apparently not in my case...
I would love to have someone from apple tell me what else to try. To let me know how did they fix my fix, so now my battery lasts only 7 ours with 6 on stand-by and 0 apps running in the background.
PS. If someone with both iPhone 4 and 4S read this, please tell me how do the signal bars from your carrier behave. On the table, next to each other, on the 4 I see four bars and the 4S has only two. Can this reception difference be the the battery killer? Is this a case to have my 4S replaced?
Thank you.