it really depends on the rotation. we for instance have night float which is cool. on a floor month i average around 64 hours a week. one week i nearly hit 80 with 77 hours and thats because it was my turn to work saturday which is a full 24 hour shift plus the 3-6 hours post call to wrap things up.
other rotations are 40-50 like ortho which is a no call month. you have to ask the program when you interview. but, all in all its not bad these days with caps and new work hour rules.
good luck....