On most rides, this here's what's in my pack (most of it actually goes into my Dad's old Mafac repair kit):
1. Spare 29er Tube - JUST in case
2. Park self adhesive patch kit - JUST in case the JUST in case goes down...
3. x2 Spare Hangers
4. x2 Soma tire levers
5. Soma Multi-tool
6. Burt's lip balm
7. 10spd quick link
8. ZIP Ties.
9. Park 3 Way for gettin' my gorilla-force torque on
10. Leatherman Squirt PS4
11. Park CT-5
12. 2 spare seat post bolts (I've broken them in the past - sucks to have to not sit down...)
13. Lezyne Alloy Drive Pump
14. Spare chainring bolt - I've cracked them in the past - listening to a creak on a long ride is for the birds.
15. Those little nuts on the valve stems? I can't tell you how many times I've used these in MacGyver style trailside repairs.. Thus they stay.
16. "Voodoo Medicine Man" Patch. This was my fathers while serving in Vietnam for the U.S. Air Force. He gave it to me when I was a kid. It's got all kinds of major Mojo and fights off the evil trail nasties. It goes on each ride no matter what.
If anything stays at home it's typically x1 tire lever, x1 hanger, lip balm and Leatherman.
Nutrition depends on the length of the ride. If it's cooler out, and it's below 20 miles, then gel's or shot blocks are fine. If it's hot out and it's 20+ miles, I need real food...