Due to the nature of my work, I usually have to carry around more than just a wallet's worth of things. As a result, I take advantage of the fact I have to carry around a bag by putting more things inside of it. The following are the contents of both my wallet and "murse", or man-purse for the lay:

Wallet:
3 Credit Cards - Visa/MC/Amex
Bike Birth Certificate (7 cycles)
Blue Cross Insurance Card
LoJack ID card
Costco card (god I love that place, where else can you get 5 gallons of ketchup?)
Blockbuster card (used once)
Bartpass (with 15 cents, how embarassing)
Half a ticket to the Parkway Speakeasy theater in Oakland
LA Fitness pass (my brother's... I use it when i'm in LA)
Calling card (in case something happens to my cell phone)
Triple AAA card
Albertsons' Preferred customer card
CA Driver's License
Necessary currency

Murse:
Many note-taking devices (8x11 as well as 5x7 for easy access/transportation)
Gripmaster - Light Tension Blue
6 AAA Batteries
ANCIENT mp3 player (that takes AAA batteries)
Lock and key
2 Ball Point pens (one blue, one black)
24 Hour fitness card
Ink Cartridge in package for recycling
Floss
Work ID
Some yellow post-it with "Geary and Spruce @ 830" written on it, no idea what that was for
Toothbrush w/ single serving toothpaste (from airplane)
Camera bag
CD (Quittus: Music of South America)
Index Cards
Clif Bar

If anyone thought to piece together my personality from the contents of my wallet/bag, I'm not sure it would be an accurate reflection of who I am. I bet they would think I'm a fairly healthy/active person (not 1 but 2 health club membership cards, a cliff bar, and a finger strengthening device, dental hygiene materials), environmentally conscious (empty printer ink cartridge in envelope to be sent to a specialized recycling center, recycled paper pads), somewhat financial responsible (carrying some semblence of cash/credit), as well a varied taste in music (south american CD, mp3 player w/ an ecclectic mix of music).

Not that any of those are misgivings, but they are lacking.

The few things I would add:
a guitar pick
my camera (it would have been hard to take a picture of my camera with my camera unless a complex system of angled mirrors was constructed)
skateboard
a few pncils
some sand (from the beach)
a shuriken (6 prong if possible, but 3 would do)
a 8x11 mosaic made of skittles depicting santa and jesus in mortal combat
and a flask (8oz of tequila)

hmm... i think that might be it... possibly more, but then it would start to get heavy.