With so many series to consider, this is not an easy question to answer. In the end, my choice goes back to the original one with James Tiberius Kirk, Spock, Scotty and 'Bones'. I was going to pick the fantastic performance put in by Dynasty stalwart Joan Collins in 'City On The Edge Of Forever' but finally had to go with 'Kahn' from 'Space Seed'. Yes, for me, the best ever is that wonderfully talented hunk Ricardo Montalban.
How about you? You can pick from any series you like - even 'Star Trek - The Next Generation'!