I don't know, I mean, Buffy's always kinda hot. OK, maybe not always, I don't find her particularly attractive in season 1 'cause well, she looks too much like a kid to me which of course makes sense, her being be 16 and all that. I also don't like how she looks in season 7. She looks older than she is, her clothes and hairdos are boring, all that incredible hair porn from the previous seasons is just suddenly gone and I'm not sure why, maybe it's the lighting or the make-up or maybe the actress was just tired or something but her face has this unhealthy look. Weird, I mean, yeah it makes sense plot-wise but still, I don't like it.
I vote season 4.