It's bike riding food. That and fig newtons.
Hmmm, in my seat bag I have:
2 spare tubes, 1 700c and 1 24"
patch kit
multi-tool
ball wrench
compact screwdriver
tire pressure gauge
spare stem
spare stem caps
tire levers
small pack of bandaids and antibiotic cream
In my camelbak-equivalent:
Driver's license
cell phone
bike lock
maps
glasses
money
debit card
keys
foodal items - dates, raisins, butterscotch, bananas, PB crackers
water IN the camelbak-equivalent reservoir
SPF 45 chapstick
If the ride is > 50 miles
- extra bottles of propel
- extra bike shorts
- rain gear
- extra gloves
- spare 24" tire (lashed to my rear rack)
- sample size sunscreen (for touch-up)
on the bike:
the seat bag
frame pump (Topeak Morph)
however many water bottles will fit under the frame pump (usually one large, one small) containing watered down gatorade or propel
Cyclometer (I forgot that one, LOL!)
On my person:
helmet
hair band (and I DON'T mean an 80's glam rock musical combo)
gloves
sunglasses ($10 from the hardware store, basically tinted safety glasses)
bike shoes (in the hopes that some day, I WILL clip in again)
The camelbak-equivalent of course
Slather up with sunscreen which usually lasts 'til the end of the ride
Things I'm going to add because I have them now and didn't use to:
digital camera
digital video camera if multi-day (slightly larger than the still camera)
spare cell phone battery, fully charged and in a heavy duty ziploc bag
Things I'm going to add after reading other people's lists:
Magnifying glass