My informal list:
- Tees - long and short
- Balls - 6-9 soft/feel, 6-9 hard/distance
- Tape (for fingers cracked raw after many rounds in the desert)
- Insect repellent
- Rain cover
- Rain gear - I keep a Microsoft Great Plains water resistant pullover
- Lighter, cigar punch, portable cigar case (with cigars, naturally)
- Ibuprofen / anti inflammatories / aspirin
- Eye drops. In case you have to play soggy ground and catch the ball fat -- and you get a blast of grit, grass, and mud in your eye.
- Ball mark repairer - and a spare one
- Ball markers / dimes
- Spare change-- be prepared - maybe keep a $20 bill stashed for emergencies
- Towel - maybe add a spare for rainy days
- Water - at least 28 oz/liter
- Energy bar - I carry an apple if it's hot or I had to jump out without proper breakfast
- Also great for high energy and protein is turkey jerky. Maybe some gum
- Whisky flask
- Um... clubs. I carry three wedges (Cleveland 56 sand, Cleve 60 lob, Titleist PW). My driver is a King Cobra, and my three-wood and five-wood are Callaway Steelhead Plus (love them).
- Spare pencils -- for scorecards
- Sharpie -- for marking balls
- Spare cleats and cleat tool... although in truth you should get any cleats replaced or changed at the pro shop prior to your round. And I have never had to replace cleats during a round.
- Glove and spare
- Bandages -to repair blisters
- Groove / club cleaner
Want golf balls with an image on them for a special occasion?