Scientific American is carrying this interesting article which details just how accurate "accurate time" can be:

The best reported uncertainty [of a cesium atomic fountain clock] at the time of this writing is about 6 x 10-16 for the NIST-F1 fountain standard ... Put another way, if the frequency standard could be operated indefinitely as a clock it would neither gain nor lose more than a second in 50 million years compared to a perfect clock.

Something tells me one of these cesium gizmos will be more expensive than those Breitling watches I was fascinated with a few months ago. But not as stylish!

I need to get out more...