Like about the phenomonally cute Alyson Hannigan as Willow. I'm watching the show in its Willow's-not-yet-blossomed stage, when she was at her most awkward socially but had her skills (and the eye of Oz; I just saw the episode where he's flirting with her while holding that animal cracker).
I'm sure it's been said before, but I'll say it here: I like that Willow's perhaps the nerdiest character, and that she's also the character who ends up with the healthiest love life/sex life. She winds up with good, caring partners, and is good and caring to them as well. No one she falls in love with turns out to be a vampire (at least, I don't think so...) or an abusive type, or otherwise so utterly wrong for her that there'd be a huge risk for her. Willow lives through tragedy and heartbreak, certainly, but that doesn't happen because of any mistakes she makes. She finds love, and it's good love.
As a nerd, I gather hope from that.