In S1? Doyle, hands down, he was dark and funny, not easy to pull off. I've always been a Wes fan, even in Buffy I thought he was hilarious. If the vote was expanded throughout the entire series, I'd have to go for Wes, but S1 Wes vs. S1 Doyle, and it's definitely Doyle.
Wes barely even contributed in S1 from a in-story POV, he added character dynamic, but wasn't a great help to the team like he became later on. In the end, Wes honed all of his abilities and became a real champion (early S5), but in S1 he was just a mess.