it depends on what you are looking for. E36 M is a much more "raw" car than an e46 non M... resale in the long run you will be safer with the M3, assuming mileage and condition are kept in tact. The e46 non M will depreciate far quicker. The M is about bottomed out in that price range...
2006 M3 vert, carbon black, black interior and top, 20" EXE Konkourse wheels, BSW stage 1 upgrade, Tein H tech springs, Boston subwoofer.
2008 328xi sedan, 18" 335i coupe wheels
" It's not what you say, but how you say it