What gadget do you use the most?

The New York Times recently reported women are suffering from back pain due to their trendy, over-sized bags that are stuffed with goodies. One of their interviewees, Chloe Thompson, said she had more than $2,000 worth of stuff in her bag, including “my iPod, digital camera, cellphone, glasses, sunglasses, makeup kit and a ton of other belongings."

The question is, what gadget do you use the most?