Heart rate is a very personal thing, and there's nothing to replace a lactate threshold test done in proper lab conditions, in my opinion. (Exercising with various sensors on.)

Based on experience, though, I assume my max to be in the high 190s. When I do intervals, I push to 185 for short periods or time, and I can also keep that when going up a hill. That's about the HR I race at as well. For my long runs I try to stick around 160-165 but talking with running buddies brings it up by a good five beats. Cycling at low intensity I would be between 120 and 150 depending on the terrain, assuming no monster hills or sprints.

I used to be really scared of my heart rate. I thought the Polar would set off an alarm at 200 the first time I wore it!! (no, that's not interference.) I spoke with a cardiologist-friend and he told me not to worry about it.

I turn off the beeper on the heart rate monitor though. I don't like to hear other people's beats either, but that's not a big deal. If it's useful to you do keep it on.

With training I've found that I can run much faster than before with the same heart rate. Your mileage may vary!!