Looking for an energy-efficient way to talk business during road trips? This Iogear Bluetooth speakerphone mounts to a car windshield and gets a charge from the sun, even on overcast days. The unit takes about 10 to 12 hours to fully charge; a charge gives you about 12 hours of talk time. One caveat: Minnesota and California don't allow windshield mounts, so use the speakerphone's included visor clip if you travel in those states.
Cost: $59.95