Any resting heart rate above 0 is good.
Mine varies a lot. When I'm relaxing in bed at night after a few bike recovery days, trying to get to sleep: low-40's. Sitting in the docs office after 32 oz of coffee, a couple of diet cokes, and having a stressful day: mid-70's.
Overall it has come down significantly from increased exercise and weight loss.
I was on prednisone for a while - nasty but necessary. It jacked my resting heartrate up to 90bpm. Glad it was just short-term.