I don't really have a vote here. Somehow, none of the female leads of TOS did much for me. Which is odd, since I grew up watching the show, so you'd think it would've shaped my standards of attractiveness. Maybe the timing was wrong. There were certainly plenty of guest stars I found stunning, but the regulars didn't appeal to me much.
Angela (communications) appeared three times, I think, but she wasn't terribly significant.
Although it's ambiguous whether Barbara Baldavin's character in "Turnabout Intruder" was actually Angela. She was credited that way, but called Lisa in the episode. Also, she was only communications in TI; she was a phaser tech in "Balance of Terror" and in life sciences in "Shore Leave." (Baldavin was also in deleted scenes filmed for "Space Seed.")