In many ways one of the most progressive shows on any network, I consider Buffy to have shown audiences one of the most honest and respectful depictions of a non-traditional (i.e. lesbian) relationship on prime-time. While the WB did hold them back to looks, touches, and dialogue (and I suspect that the couple's first on-screen kiss in "The Body" had something to do with why they changed networks), the show treated Willow & Tara's budding relationship with the same respect they gave to the heterosexual couples. And when they got to UPN, who gave them free reign over the show's content, they became exactly like all the other couples on the show, and were even allowed to be seen in bed together--naked (*gasp*).
Sadly, Tara was killed at the end of the sixth season. But, unlike in other shows, "dead lesbian syndrome," where they kill the lesbian lover and forget she existed, didn't affect the show at all. Tara's murder was treated as any other character death, and had lasting repercussions far into the show's final season. And while they could've easily dismissed the Willow/Tara relationship as "experimentation" and sent her back into the arms of, say, Oz (her lover from seasons 2&3), the writers embraced her new lifestyle and allowed a relationship with another woman (this time, a potential slayer) to develop over the last few months of the show. For this, I applaud Joss Whedon and his writing team. Why can't more shows be like this one was?
AfterEllen.com's Buffy Page