Xander Harris is one of Buffy Summers' two best friends. From the beginning, Xander has no problem accepting Buffy's role as the group's primary (and in the first season, really only) fighter. He responds to Buffy's position as a Slayer with nary a comment about the extraordinary circumstances of a girl being a fighter or a leader. Instead, he just accepts it, telling a captured friend, "It's cool; Buffy's like a superhero". The show also demonstrates some of Xander's feminist credentials by his casual acceptance of and outward gratitude for Buffy's frequent rescues, thanking her in some instances and in another saying, "I have a plan. We wait. Buffy saves us". Xander is both aware and comfortable with his role as back up, understanding that the majority of the fighting will be done by Buffy herself. He is able to enthusiastically be a "slayerette" and not the lead, going so far as to declare that "I laugh in the face of danger. Then I hide until it goes away." And he is incredibly aware that his strength is not brute force but something different. Xander has several shining moments on the show in terms of fights; but they normally revolve around either being around as back up, or as playing to his own strengths. A Chandler-esque character, Xander is more verbal than physical. And so some of his greatest moments in the series in any light reflect that particular trait. He is able to talk a recently zombified classmate out of blowing up the school, telling the delinquent that, "Being blowed up isn't walking around and drinking with your buddies dead. It's little bits being swept up by a janitor dead and I don't think you're ready for that" while standing in front of the only exit. He isn't overly macho in the scene, or full of bravado. As he says, "I like the quiet".
His verbosity comes in handy in other, more intimate cases as well. He is at times angry and tempestuous; he isn't a perfect guy or friend. But when the chips are down, he is there when it counts. And he is unafraid of showing the full gamut of emotions and opening up to friends. He bucks up Buffy by saying, "Let me tell you something, when it's dark and I'm all alone and I'm scared or freaked out or whatever, I always think 'What would Buffy do?' You're my hero." His sexual escapades also align him with what would be considered the typically feminine response, and the show does not belittle or mock him for it. The show in general is more about sex within the confines of an emotionally satisfying relationship than simple bed-hopping, and Xander does not buck the trend. The first time he has sex, he is the passive party. The second time he has sex, Anya, his eventual girlfriend, disrobes in front of him as he gets her a cran-apple juice box. She explains that they should have sex and then move on to their separate lives. Xander, in a bit of shock tells her, "It's just we hardly know each other. I mean I like you. And you have a certain directness that I admire. But sexual interc-- What you're talking about, well -- and I'm actually turning into a woman as I say this -- but it's about expressing something. And accepting consequences". Although the speech contains some problematic language, it is made less so by the fact that "woman" is not a less-than in the circle Xander runs in. Women and womenly emotions are not derided or seen as weak. Xander accepts and verbalizes that for him, sex is more than simply physical sensations. It is an example of Xander both exemplifying a stereotypical feminine quality and highlights how that is not a negative.
Perhaps my favorite thing about Xander is the fact that he is friends with a girl he has a crush on. In many shows - and in many instances in life - the relationship between a guy and his crush is not a true friendship. Instead of seeing Buffy as "a girl to hang out with on a pursuit of potential future bliss", Xander simply sees her as "my best friend whom I also have a crush on". The differences between the two positions is huge. Xander reacts less than well to Buffy's rejection, yes. But he gets over it, in the very same episode and in the very same day. He deals with her rejection without losing her friendship. He handles the fact that she likes another guy, and continues to do best friendly things with her like watch Indian musicals and hanging out at the local club and at her house and in general. Instead of disappearing or believing that Buffy "owed" him something for the friendship ( unlike Jeff Fecke's Nice Guy ®, who believes girls "used him for emotional intimacy without reciprocating, in kind, with physical intimacy"), Xander stayed Buffy's friend because he values her as something more than a potential girlfriend. He values her as a person, and he loves her both romantically and platonically. And that is seriously feminist, and kind of radical for most forms of media. An example to the contrary would be Marty on Gilmore Girls, but he is far from the only one. And that "radical" nature makes Xander one hell of a (fictional) feminist icon in my book.