The 1960s Star Trek show (calling it tos sounds rude and untrue as well!
) is certainly my favourite of the various Trek shows. I like the characters, the humour and the sense of fun and adventure.
It's one of my favourite sci-fi shows generally as well (probably in my top five - stiff competition of course from the likes of Doctor Who, Blakes 7, Space: 1999 and Sapphire and Steel). Generally I prefer British tv overall, but again Star Trek is in the top rank of those American shows I like to watch.