Jackson x Melissa.
Originally they were just my two favorite characters, but then I started thinking about what if they got together...and then, I was hooked on the pairing. It screams 'Bad Boy meets Good Girl' at me. But honestly, they're so different, yet they're so alike. While Melissa is weak, Jackson is strong. While Jackson dosn't care, Melissa cares too much. No one I've seen has really stopped to evaluate their possibilities, and hey, maybe I am biased because I like them both and I hate Taylor, my view still stands.
I also like Abby x Eric, Nathan x Daley.