That is a terrifying feeling. I start freaking out and hyperventilating, wondering where I could have left it, and if someone might have taken it.
Ken Rockwell always says that with most cameras, the photographer uses them for a couple years, heck, even a couple decades, and then sells the camera. Because of the strong possibility of selling a camera eventually, I don't want to engrave my information on it, but I also don't want to leave it unmarked.
Enter the Dog Tag.
I had four of these made up from a company called DogTagsOnline.com. The tags, ball-chains, and black rubber silencers cost me $17 total, shipped to my place First Class Priority Mail.I tossed one on my camera bag, one on the D300's ring, one on my neck, and I've still got one to spare.
Now if I misplace a camera, or have it disappear on the spoiler of a Dodge Neon, I am confident that if a decent person finds it, it can be returned to me!