You'll be real happy that passcode is on there when you leave your iPhone somewhere. If you have a choice, leave it on... you get used to it after a while.
That might be it. My phone helps me in a part time job, and my Boss put it in, even though I don't handle anything sensitive. I guess I have to speak with him.
If you delete the exchange email, you should then be able to turn off the passcode lock. That's assuming you don't want email. If this is a work phone, then of course your company decides what you can do. You should be able to up the time between when the code needs to be entered to an hour, that will keep the nagging down to just a few times a day.