As a program driven mainly by the notion of "girl power," "Buffy the Vampire Slayer" has lent itself to studies of the role of the woman/feminine in the television landscape. However, Joss Whedon's creation is home to several strong male (though not necessarily masculine) presences, who bear some looking at.
In this writeup, I'm going to focus mainly on relationships developed in Season 3, which is arguably the strongest season for positive male roles (and in a twisted way, The Mayor fits the bill).
I will also be disregarding the characters Angel and Spike for the most part, as their vampiric nature has already lent them to a lot of reading (and frankly, they don't interest me nearly enough).
The Father -
Perhaps one of the most dominant figures in a person's lives, the father is suspiciously non-present (in the traditional sense) in "Buffy".
Buffy's father, Hank, is a nominal force in her life in early seasons, but grows more and more distant with each passing year - so much so, in fact, that he does not come to Joyce's funeral in "Forever". Nor does he make an apparent effort to gain custody of Dawn afterwards.
We meet Xander's father only once, in "Hell's Bells" (and also in a dream state in "Restless"). He is a verbally abusive (and possibly physically abusive) emotional absentee. He publically berates his family, the "family" of the bride, and hits on Buffy. In no way does he represent a positive role model in Xander's life.
And yet, both of these characters get the paternal love and support they need, somehow. It's difficult to see how either of them could live without the influence of Giles in their lives.
When Giles first meets Buffy in "Welcome to Hellmouth", his manner is not unlike an early adoptive parent: eager, ready to please, but still trying to conform his new charge to a role (daughter/slayer). It's obvious that the girl at first disappoints ("The world is doomed...") - Buffy wants to define her own life role, she doesn't like him, she wants to party, she has a personality. She is not exactly meeting his standards for a slayer.
However, even as early as the third episode, "The Witch" it's obvious that his role of Watcher is being melded with his role as surrogate father ("I make allowances for your youth, but I expect a certain amount of responsibility, instead of which you enslave yourself to this, this...cult!"). His disapproval of her decision to try out for cheerleading is as much based in his duties as his personal taste for the "sport" (something, interestingly, that Joyce would later state more clearly on her own behalf).
Even if Buffy does not yet recognize Giles as a fatherly influence, his own realization of this turn of events is all too evident in "Prophecy Girl". Upon realization that his daughter/charge is fated to die, he spends a sleepless night working out how to prevent it. The crestfallen look on his face when Buffy rejects her role (and, by association, him - since it's obvious that her own perception of him is still very based in his role as a Watcher), seals his change.
Of course, as Buffy's relationship with Hank Summers becomes more strained (hinted at in "When She Was Bad", but fully realized in "Surprise"), she turns to Giles to fill a role he himself had already taken up. Her plea with him (in "Surprise") to take her to the ice skating show in place of her genetic father, is the most obvious sign of this switch.
Giles, whose initial appearance had been fussy and effeminate, becomes more masculine the further his paternal role is taken. Initially happy to sideline himself in the battles, while the strong (and obviously emasculating) slayer takes on the forces of darkness, he takes a more and more active role - at first, only in moments of desperation ("Prophecy Girl"), but increasingly as a part of the battle squadron of Slayerettes ("What's My Line, Part 2").
He's allowed a strong moment of glory when facing his past in the visage of Ethan Rayne ("Halloween"), but falls to desperation when another old enemy appears ("The Dark Age"). Again, Buffy has to deal with a flaccid father figure - but this one pulls himself back into her life at the right moment. Giles' brief fall and return only served to solidify his own surrogate status.
It's interesting to note that Giles is at his most masculine when protecting or avenging women. His most brutal display of violence, against Angelus whilst wielding a flaming baseball bat, came as a move of passionate rage after discovering the dead body of his beloved Jenny Calendar ("Passion").
(More to come...PLEASE keep in mind this is my first E2 post. Sorry for breaking protocol, folks. Kill me. Please.)