An some of us have them built into our notebooks so there's nothing extra to buy, carry, waste a USB port, etc.
ThinkPad ThinkLight
Phones: Samsung Galaxy Gio, Motorola KRZR K1, Nokia 1600b
SIMs: 7-11 SpeakOut CA, tele.ring/A1/Yesss AT, Mobal
R.I.P.: UM, UM+