I thought the Lamia herself was well done too. She was quiet and creepy and not overtly sexual or over the top. Just a quiet menace.

Yeah, I don't always get the impression Gwaine thinks of himself as a knight. More one of the lads, who happens to be a good fighter. I think he likes hanging out with Merlin where he doesn't have to be so knightly all the time. Not that he tries to be knightly the rest of the time. :-p