My mother is an RN (diploma), and has consistently been earning 50K-65K a year for over 5 years. This is not a bad salary! However, she does work the occassional odd shift, and does 36 hr/wk (3 12-hour shifts) so that she can have more days away from work - it pays her for 40 hrs., and provides full-time benefits.
Anyway, she's talked me into nursing school, and now I'm in the junior year. Starting pay is much lower ($15.80/hr), but shift differentials can make an enormous difference - only $3/hr extra for second shift, but then $13/hr extra for weekends. For a new grad, that isn't bad!
Perhaps there are regional differences?? My mother and I both live in North Carolina. The cost of living is low, so the pay is not bad. We don't have unionization, and perhaps that makes all the difference!