Of course! You want one with a heart rate monitor chest strap; the watch-only ones don't do a good job of monitoring your heart rate because you have to press a button to take a reading.
I like the Garmin watches; I like their GPS, and in fact just ordered a new one yesterday! So my head is full of stats and details.
I got the basic version without the chest strap, because I already have one. They do work on the treadmill. The other two versions have the chest strap included. I did a LOT of research on this one, and settled on it because it had all the features I wanted.
However, you may not want one with the GPS, which bumps the price up a bit.
Polar is well reviewed by your fellow SP users here; Again, you want one that has a chest strap.
Here's a below-$100 model: www.amazon.com/Polar-Heart-Rate-Monitor-Pu
I got one at Walmart (a Sportline) for around $50; it was a great watch! The only complaint I had about it was that once it started, it wouldn't stop tracking your heart rate and calorie burn until you separated the watch and the chest strap far enough, which was annoying since I can't really get it far enough away in the car. So I had to take note of the final calorie burn at the end of my workout. Otherwise, it was a great entry-level model for getting started.