I've watched them all sooo many times already. Well not TNG, I've only watched that all the way through twice and I'm not watching it again to prep for anything
I will be watching ST:XI as prep several times before we get the new movie.
I am actually planning on watching some TOS in the near future so that might be a good prep. Though I have seen TOS far more than the other series I have seen it longer ago so the refresh will probably be good for this movie.