The Motorola Motoactv http://www.motoactv.com is an Android watch targeted to runners, so it has ANT+ as well as GPS and Bluetooth. Though it's much more expensive ($249), and doesn't have an open API. It pairs with Android phones and displays texts and lets you take calls with your headset.

That said, I have one, and use it for running and love it.

Is ANT+ popular in the US? I see companies like Nike promoting it, but I've never laid hands on a device supporting it (I'm in Europe).

It's huge in Europe and the US amongst cyclists and triathletes. All UCI ProTour teams use it, with the exception of the teams sponsored by Polar. A good ANT+ system can do some very clever things that provide substantial competitive advantage. Many triathletes use the iBike Aero system, which in conjunction with a force-sensing power meter will calculate coefficient of drag in real time.

I see it in finiteness devices. It allows you to integrate things like heart rate monitors and cadence sensors on bicycles or running shoes with watches and smartphones.

Once a device has ANT+, it is the logical tool for data transfer as well, so devices like Garmin watches come with an ANT+ USB dongle to integrate with your computer.

But to be fair, ANT+ data transfer is super fucking flaky. I would say that I get my running data off my Forerunner about 50% of the time when the watch is physically touching the USB dongle and 0% of the time when it's not.

And, nothing ANT+ seems to work under Linux. So let's skip this for a while and stick to Bluetooth or USB; it works better and works everywhere. You have to plug in your watch to charge it anyway.

Most of Sony Ericsson's Xperia line support ANT+, and I use it with a Garmin heart rate monitor transmitter.

http://www.thisisant.com/pages/developer-zone/android-api

It's catching on in certain markets. Garmin has been dropping it into a lot of its cycling gear.

https://buy.garmin.com/shop/shop.do?cID=160