I think HRM is more useful than Pedometer, because the heart rate during exercise is normally a better indicator for the actural intensity, especially if you want to burn fat more efficiently. I bought a Timex HRM more than a year ago for less than $30. It's pretty handy to use. But the battery died few months ago, need to find a place to change it. There are also other more high-end HRM, just yahoo HRM, you will find a lot.

polar 是大牌，reebok也很不错。我用reebok的一年多了，配胸带的，很好用。