Using a mobile phone while driving is illegal. As such, if you want to make or take phone calls while operating a vehicle you'll need some kind of hands-free system and if you don't have that built into your car already, you're best choice will likely be a headset, such as the Jawbone Icon.
The design aesthetic leaves no doubt that the Icon is descended from the same product line as the Jawbone Noise Assassin and Jawbone Prime before it. Although no matter how stylish the Icon looks, it remains inexcusable to wear any Bluetooth headset while not actually inside a car. Furthermore, the names of the different designs - The Thinker (the one we have here), The Rogue, The Hero, The Ace, The Catch, and The Bombshell - are a tad silly and can't justify the £60-odd price tag in isolation.
The Icon is the most compact Jawbone yet, measuring 45mm x 18mm x 24mm which, coupled with its mere 8.2 grams of weight, makes it practically unnoticeable in the ear. This is helped by the large choice of earpiece fittings so you should have no problem getting the Icon to stay in place in your ear.
One notable plus to the Icon is that it features a physical power button. Not that you'll need to turn it off very often with a claimed 10-days of standby power. The 4.5 hours of talk-time isn't outstanding, but anyone having long conversations while driving is clearly Doing It Wrong. In a slight regression, the Icon has a micro-USB port for charging, rather than the fancy magnetic dock charger of its predecessor. However, this does mean you can use someone else's micro-USB charger if you've mislaid the Icon's one.