My truck key, my gf's car key and alarm doohickey, keys to all the cablelocks for my guns, house key, cigar punch, LED flashlight, tiny Swiss Army Knife, and a bottle opener.
I try to keep my keychain as concise as possible. I can't understand how some people can walk around carrying these monstrous things with little stuffed animals and charms and other useless crap all over them. Besides, a heavy key chain does major damage to the ignition in your vehicle by swinging back and forth while you drive.