Two devices that never really needed to be combined have been with the Bluevoice, a combination Bluetooth headset and watch. Due to be released in November (but heavy promotion begins in 2007), the Bluevoice solves the problem of "feel[ing] like a cyborg with a [B]luetooth headset in your ear all day." Yeah, now you just look like a total dork.
The Bluevoice is normally worn as a wristwatch, but it can be unclipped and held to an ear when you receive a phone call. Both an analog and digital clock version will be released, with the fancy-pants analog costing $127.95 and the everyman digital coming in at $119.95. Any ideas that you may have about it being easier, perhaps, to just wear a normal wristwatch and answer the phone are entirely unwarranted: this is the future and you'll grow to love it.