The V1 from BlueAnt ($130) is the first headset to respond to voice commands, and it does a good job within its limits.
The headset is limited to a list of voice commands, such as dialing up to 8 numbers programmed into your handset's speed dials. Just push the V1's main button, and a charming man's voice will prompt you to "Say a command." A command of "Dial speed dial 8" results in just that.
Voice-response systems have their own limits. The device isn't smart enough to know when you want to start talking to it, so it requires a quick push to its main button. And to end a call, you need to fumble for the phone, or trust that the other person has hung up (although the V1 eventually confirms "Call terminated").
The V1 shines most, frankly, in managing itself. Other Bluetooth headsets require multiple button pushes and counting LED flashes to know what's happening—if the headset is ready to link with a cellphone, for example. With the V1, the command is "Pair mode." The headset voice not only responds that it is ready to connect to a phone, it talks you through the process with the handset itself.
In fact, when you first turn on the V1, don't bother with the manual. Just stick it on your ear, and the V1 walks through setting itself up and connecting to a cellphone. Nice. It at least works better than following the manual, which frustrated me.
The voice-response system, called BlueGenie and made by a company called Sensory, is surprisingly accurate for such a small device. It's better than the voice system in my Blackberry phone. I can access the phone's voice prompts, by the way, with a command through the V1.
The V1 also goes through a training session, which trains you and not the headset, and is set in its ways. You learn, for example, that you can't interrupt the headset—it must finish its prompt before you can dictate a command.
Incoming calls, by the way, get announced with the number they're coming from. Picking up is as easy as "Answer," and "Ignore" throws them to voice mail.
Sound quality is good on the V1, with calls sounding as clear as on any headset I've tried. BlueAnt has a reputation for making good Bluetooth headsets, and it has pushed the edge with the V1's voice system.