I do. Otherwise it's too hard to get a accurate reading.
This. I don't want to think I have half a battery left by the icon but in reality I've got < 20% remaining. I have mine turned on so I know how much I have and if I need to conserve power if I'll be away from my charger for a while.
I always have. It lets me take care of the battery. I don't charge it if is over 60 %, unless i know I'm going to be away from a power outlet for a extended period.
Side note: Anyone use the jailbreak app battery detective? Pretty interesting. I have it installed on both my 4 and 4s, let's u know how many charge cycles the battery has had (450 for my 4 34 for my 4s, it's max capacity vs current capacity). Pretty cool. Although maybe I obsess to much.....
Considering how little space it takes up in the status bar, it almost doesn't make sense not to have it displayed. As others have said, I like knowing exactly how much juice I have left and not having to rely on an inaccurate battery icon.