Different heart rate monitor for calorie calculation needed

I currently use a Garmin 910xt to track my swimming.biking/running paired with Garmin chest strap heartrate monitor. Although I feel th eheart rate monitir works and is accurate I don't like the strap around my chest.

Are there any decent wrist (or other?) worn heart rate monitors with good calorie expendature calculations that anyone reccomends?

I want this primarility for calorie expendatures while doing weights, crossfit, and other cardio workouts where the Garmin GPS doesn't need to record my distance/speed...