Women got robbed. Female guest stars were usually young and pretty. We got no eye candy other than Spock and he was a regular.
He's not enough for you?
The hottest season 1 guest star for me was the guy who appeared in one scene in "The Man Trap" as the
fake crewman/form that the M-113 creature took to try to get to Uhura. (The pic doesn't really do him justice.)
But Khan was very hot, too.
Out of the last 2 seasons, guys that stand out are Flavius Maximus ("Bread and Circuses") and god Apollo ("Who Mourns for Adonais"). Ensign Garrovick was good-looking, too.
- Gary Mitchell. Elizabeth Dehner. (Same age. A tie, I guess.)
- Khan. Marla McGivers. Khan middle-aged, Marla still young.
So what? Ricardo Montalban was much hotter than the woman who played Marla.
As for the women, I don't actually find most of the S1 female guest stars sexy, apart from Andrea, Vina and Helen Noel. The women in "Mudd's Women" had silly haircuts and weren't all that anyway. Among the regulars, Uhura was really hot and gorgeous, but Rand had that silly beehive on her head, and Chapel proved that platinum wig didn't suit Majel Barrett at all. She looked much better as Number One. It also didn't help that both of them were bland and whiny. At least that was rarely a problem with the male guest stars.
Seasons 2 and 3 are better in terms of female guest star hotness: the Romulan Commander, Marlena Moreau, Zarabeth, Nona ("The Private Little War"), Kelinda ("By Any Other Name"), T'Pring, Marta ("Whom Gods Destroy"), Isis in her human form ("Assignment: Earth"), what's-her-name played by Julie Newmar...
I've never noticed it before, but she looks a bit like Jane Leeves (Daphne) in the early seasons of Frasier.
http://www-personal.umich.edu/~fwu/frasier/pictures/frasierpics/bioleeves.gif