I remember the first Star Trek i watched was a VCD of Wrath of Khan that my dad bought (he is a huge TOS fan) it was then that i fell in love with Star Trek. but TOS was too much for me,i barely watched a few episodes of the series, it was too far from my time.
2-DS9 (some episodes are horrible)
3- ENt (Not great but fun)
5- TNG (The most boring,too much talking,too much nonsense in the Holodeck,the only series that was nerdy ughh i only like a few episodes)