It depends on whether my son is with me or not. If he isn't, all I have are what's in my pocketses (no purse): wallet; phone; house, mailbox, & car keys; small notebook of some sort; pen; rosary; and sometimes my Pokéwalker. I try to remember my watch, too, but since the baby likes to try to take it off I don't always remember.

If he is, there's also the diaper bag: between two and six diapers (if I've refilled it recently or not), wipes, a cloth diaper (for spills), a changing pad, a t-shirt for me, a t-shirt, a pair of pants, and a romper for the baby (used to be more than that, when he was pukier and his clothes were smaller), one or two kinds of snacks, one or two toys that can be gnawed upon, and pads for me.

A mini first aid kit would probably be a good idea, but I don't have anywhere to put it. (The pads are a holdover from the weeks immediately post-birth, so I guess they could go; what should go in a tiny first aid kit?)