I have a headset bag which I got free somehwere containing a headset, GPS, bit of paper with useful frequencies on it, pen-on-a-lanyard (to hand around my neck. I also carry a chart (marked up if I'm going anywhere) and a hand-held radio. In my flying suit pockets go wallet, short chinagraph, sunglasses, camera, licence. My reading glasses hang around my neck as ever.
If I'm taking a passenger, I take in addition another (free!) headset bag containing a headset and a sick bag.