I have a ton of crap in my bag...
- Aimpoint book
- Divot repair tool
- Ball marker + lots of coins/change
- ~ 15 Balls - I always have to many which weighs down my bag (I'm an idiot)
- Gloves (I don't wear a glove - but just incase it gets really humid and my hands start slipping - or if I get a nasty blister I'll throw a glove on to finish my round)
- Winter gloves
- Winter hat
- Rain hood cover for my clubs
- Towels (in case it rains - I've got backup)
- Vanity bag to hold watch, ring, keys, etc, etc..
- Plastic alignment aid marker tool
- Sharpies to mark my golf ball(s)
Things I need to add... USGA rule book. I just played in a tournament last weekend and one of my playing partners had one. And it came in great use on one of the holes where we weren't sure the deal with regard to his provisional ball. He hit his first ball into the water on the right. His provisional ball into the water on the left. Then decided to take a drop and from where his first ball went into the water hazard. I wasn't sure if he could do that - but we looked it up and he was entitled to play his first ball (hitting three) based on it entering the hazard.