TOS - Cheesey to say the least, bad acting but overall fun to watch and is the original but in this case I would say not the best. Some great episodes though Space Seed, Balance of Terror, Tholian Web etc. etc.
TNG - Rocky start but had some gems in the first 2 seasons, season 3 onwards for me contains some of the best Star Trek to date. Laid the foundation of things to come, Klingon story arcs, Ferengi, Romulans, Borg. Great episodes like Yesterday's Enterprise, The Best of Both Worlds, Data's Day, Redemption, Unification etc. etc.
DS9 - Probably the most re watchable series for me but again Season 3 onwards were most enjoyable, fantastic reoccurring characters, great story arcs. Season 6/7 were the best seasons of any Star Trek series IMO.
VOY - Got me into Star Trek, again features some of my Trek episodes, Future's End, Scorpion, Year of Hell, Message in a Bottle, Timeless. I generally enjoy seasons 4-7 more than 1-3 though.
ENT - Like Broken Bow but not much after that to be honest, watched as it aired and was continually disappointed but kept hoping it'd get better. Some good episodes like The Andorian Incident, Breaking the Ice, Cold Front, Silent Enemy, Shadows of P'Jem, Shockwave and Future Tense but wouldn't consider these great episodes just re watchable... And Finally I actually like These are the Voyages it made it all seem like it was all just Rikers fantasy
Abramsverse - Really like Star Trek 2009 but not so much a fan of Into Darkness, will have to see the third installment before making up my mind fully but can certainly say I prefer the Primeline