Key Signature

Luxe carmakers have figured out that no detail is too small to seduce drivers—right down to the keys. The latest are part fashion accessory, part James Bond gadget: sleek electronic fobs that can cue the headlights, change the suspension, and unlock the doors without so much as a push of a button. Next year's Volvo S80 key will even warn you of intruders by scanning for heartbeats inside the vehicle. Just be sure to hold on tight to these new doodads: Replacement may require a tow to a dealer to reprogram the car's computer.

Land Rover
The new LR3 key can withstand a 30-foot fall onto concrete and submersion in 75 feet of water. One button can raise or lower the vehicle's suspension.

The key to the latest XK unlocks the door when you touch the handle—the car senses the key as you approach. For emergency (or valet) purposes, a mini key blade pops out so you can secure the glove box.

This new key system (available with the A6, A8, and Q7) will unlock the door when you touch the handle. A start button turns on the engine. Or you can use the switch-blade-style metal key to fire the engine manually.

The fob will unlcok doors and start the engine while still in your pocket. One button will open windows and the sunroof before you set foot in the car.

Bentley's knurled chrome-and-rubber key for the 2007 Continental is the best of both worlds: It allows empty-handed entry and start-up and, for those with 20th-century tastes, a metal key comes built in.