My trainer has suggested I get a heart rate monitor so I can determine how many calories I am burning during my workouts. Anyone have any recommendations?

Polar has some nice ones and it's good to get one that will ignore others around you. I had the F5 for years.

Good to know. I will certainly put that on my list :-)

I have the Polar FT4 or 40 and it works great. I use it all the time.

Look at this purchase long term. Do you plan to run or bike? If so out that into your thinking of what monitor you shop for. I use the bike gps watch that uses a polar strap. I get best of both worlds. Just a HRM for the gym and it is a GPS watch to track my rides and HR while mountain biking plus logs everything on the nike app so I can see my progress.

Nike GPS watch.

Most Polar straps are compatible with the heart rate monitors built in to many pieces of standard gym equipment. I personally use the FT4. I find wearing a strap around my chest to be very uncomfortable and it slides down quite a bit when I'm really pushing myself hard. I can't wait for (accurate) heart rate monitors that don't require chest bands. The technology is there and should be coming to market in a few months.

^^ the Mio Alpha is a nice strapless HRM and is very accurate. I had one for a couple weeks. I didn't end up keeping it because it wasn't great with cycling. I had to use 2 separate units and prefer one. I have no issues with straps and wonder if your HRM is a newer model or older? Could be the difference in straps and it sliding down. I find I have to tighten my straps every so often and wash them once a week or so.

I do a lot of home workouts and gym workouts. Have a Polar FT7 and like it a lot. Although it doesn't track distance on my runs, I can still track my heart rate.