Don't ever let anyone put you down because you keep a log book I do too, and rest assured it will provide you with countless memories of interesting and 'hairy' flights, as well as drunken nightstops and who were your partners in crime throwing the hotel furniture out over the balcony, and sunloungers into the pool ( complete with crew members still lying there), for many years to come!
And yes you should count B737-200/300/400/500/600/700/800/900s etc as seperate types if you are a true anorak.
Happy flying and logging mate!