I was a hardcore
fan of the Adam West show as a kid. If it were left up to me to pick and choose future figures in this line I'd go with Tut, Egghead, the Bookworm (Roddy McDowall), Louie the Lilac (Milton Berle) and the Otto Preminger version of Mr. Freeze.
I adored some of the lesser-seen and lesser-known villains, like Cliff Robertson's villainous criminal cowboy Shame and the Mad Hatter. The 1966-68 show was - at times - almost as big a part of my youth as TOS and the early years of TNG were.