for the record I also had...
1 spare tube
my hat
1 bike pump.
2 15mm wrenches (long and short)
1 10mm wrench
1 8mm wrench
1 spoke wrench
3 tire levers
2 big bottles of water
1 U lock
1 7' kryptonie cable
1 Chain tool
1 Section of extra links
1 presta adapter
1 pressure gauge
Flat repair patches (tube and tire)
A bunch of pencils and **** for school
and FWIW the bags plenty light
I have a messenger style bag as well, I just don't see it being anywhere NEAR as comfortable.