If I'm going to work: wallet, car/house keys, work keys, cellphone, and my earrings (have to take them out for work).
just out and about: car/house keys, cellphone, change, money
out bicycling: DL, credit card, eco pass (bus pass in case tires go flat and my spares do too), cell phone--all in my camelbak with my tire changing tools, mini-tool, mini air pump and extra tube(s)