I'm more a thigh guy.
Ultimately I prefer Boudicca not for the looks (Dido's beating her by far here, and it's a neck-in-neck competition with Theo and Cathy), but rather she's really the only female leader who's nice to me, even when we're both shooting for the same victory condition. She's a bit of a warmonger like Dido and Cathy, but she's not nearly as backstabby, meaning I can often declare war with her instead of against her.
Basically, I like her because she's my ally. She's not the kind of girl I'd consider pretty by any means of the word, but I'd gladly go to a pub with her.