The Sonicare Crest IntelliClean ($140) may be the most expensive toothbrush out there, but it's easily worth twice as much. It c****ines bristles that run at more than 30,000 strokes per minute and gentle sonic waves to clean away plaque from your teeth and cleans in between them and along the gum line better than any toothbrush in the world. It has a built-in liquid toothpaste dispensing system, dual speed control, and an automatic timer that beeps every 30 seconds to remind you to move to another part of your mouth and turns off after the recommended brushing time of two minutes. Oh, and for wimps like us, the Sonicare lets you get acquainted with it gently thanks to a feature that gradually increases brushing power over the first 14 uses.