Right now I wear mine just about all the time when i leave the house.

Maxpedition fatboy with:
(side pocket)
Low Db rated ReUseable Earplugs (Hearos HiFi)
256k USB stick
Vaseline lip therapy tube
Ritter PSP
Leatherman Wave
Photon II
Spyderco Military
Surefire E2E
Butane cig Lighter w/safety lock

(Other Pockets)
Garmin Vista GPS
Surefire M2
Right in the Rain Notepad
Space Pen
Energy Bar
Mechaniz Work Gloves
Snowpeak Ti Spork
Gameboy Advance SP
Small Compass w/mirror
Chewing Gum
Dangling Maxpedition Cocoon for Sunglasses

And there is usually a paperback book and CD/MP3 player w/ Koss PortaPros, plus room for more stuff if need be. If I anticipate needing more space I clip on a RollyPoly.