For those who have everything: Global Pet Finder

Worried about Fido wandering off? The Global Pet Finder collar monitors your pet’s precise whereabouts and can keep you informed of the little guy’s exact location via phone or wireless device. Other modes use its Global Positioning System transmitter to create a virtual fence and let you take walks without the hassle of a leash.
Price: $289.99 Contact: Globalpetfinder.com
Source: National Geographic Traveler