I use one of these stuck on the windscreen. It's not obvious, and looks quite cool being a steel ball about 15mm diameter, rather than crude plastic. They work very well, easy to angle and no vibration. Just a word of warning though. These are powerful magnets. They don't effect the iPhone, But don't keep it too close to credit cards or magnet strip parking tickets. I make a point of keeping my wallet and phone in different pockets.
