My wife would like a heart rate monitor watch for her Birthday. I've done some research but there a LOT of options out there. I don't want GPS enabled as she isn't concerned about distance. She wants to know that when she is out for 30 mintues that her heart rate is in the best range. I know some are alarmed for the range. I think that would be good. A calorie indication would be good. Of course time as well. One question I have is do they all require a chest strap? We have chest strap for our treadmill and neither of us like wearing it. Size would be the other concern. It can't be anythign giant. Something slim and lightweight yet easy to read on the run. Anybody have suggestions? I'd be willing to spend about $100.