What don't I carry?? After much trial and error, I cut it back to the "essentials" (all in a bag smaller than an A4 piece of paper, mind you):
Wallet, make-up (inc lipstick, lipliner, mascara, eyeliner, mirror, lip gloss & chapstick), 2 mobile phones, car keys, paper & 2 or 3 pens, perfume, daily planner, chewing gum (usually at least one packet), ipod, packet of smokes & a couple of lighters... And quite possibly a spare cardigan as well.
I did however find that carrying the kitchen sink around wasn't as convenient as it seemed at the time, so I tend to leave that at home now
Edit: I also quite often carry jewelery around with me, especially if I'm spending the night at a friend's place.