I recommend the Garmin 305 as the best value in GPS Heart Rate training:

I searched google for a way to calculate calories burned during my workouts based on average heart rate. It took some digging, but I finally found some formulas posted in a cycling forum. So, I created this nifty calculator. The numbers are sometimes quite different than what you get using caloriesperhour.com

For example, I rode my bike for 3:20 today at 16.6 miles per hour. My avg HR was 144 bpm. According to the cycling calculator at caloriesperhour.com, I burned 2500 calories in that workout. But I know that can’t be correct, based on my hunger levels and calorie intake: I consumed 2300 calories today and feel quite full right now and my energy levels are fine…and it’s almost bedtime! According to my new calorie calculator, I burned 1800 calories. That sounds more like it.

Go to my Calories Burned Calculator