TNG for me. No other Trek series even comes close (although I am aware of the issues TNG has). I do also have a soft spot for ENT, however. I've been re-watching it a bit over the past few years and it's far more enjoyable to me now than it was when it originally aired. Never could get into DS9 or VOY even though it wasn't for a lack of trying on my part. TOS is... well... meh to me. Not bad, just "don't really need it, but I don't mind that it's there". Same goes for DSC. Never seen TAS.