I have a little 'under the seat' pack. It has an Alien tool, a few individual quick patch kits, some of those ind. wrapped hand towels (like you get at a lobster dinner), my cell phone and a laminated copy of my emergency contact info plus $20.

On my Wing (behind the seat water carrier) I have my 2 H2O bottles and 2 tubes in the velcro Wing straps. Since I'm a roadie, I sometimes velcro my tevas onto the wing as well if "lazing about" is part of a ride.

I hate wearing a pack... so I've become a bit of a minimalist.