9. Sela
The human/Romulan hybrid of an alternative universe version of Tasha Yar. I wouldn't suggest that the new show should dwell on her past too much as it'll be quite the headache for new viewers. Best just to say that she's pretty much the only Romulan you'll ever pick out in a crowd if they all had their backs turned as she's the only blonde one. But seriously, Sela was awesome. She was a credible threat, who was genuinely sneaky and should have returned for more episodes of The Next Generation. She was pretty much in the same mould as Seska later in Voyager (and as much as I disliked the plotting of the episodes in Voyager during that period, Seska herself was great). Heck, I almost think I would have enjoyed Star Trek: Nemesis if they had done away with all that Picard clone nonsense and just had Sela instead. It would have had the personal element from Star Trek: First Contact that Picard had with the Borg instead of trying to artificially create it. There's a lot wrong with Nemesis, and none of it is Sela's fault. Star Trek: Online has Sela as one of the main antagonists (especially in the Romulan side of the story) and she is voiced by Denise Crosby. Crosby also appeared relatively recently in the Blood and Fire episode of fan series Star Trek: Phase II. Personally, I think if Star Trek came knocking with the Sela role again, she'd be up for it.