1. Angel (David Boreanaz)
Of course Angel is #1! Who else could it be? Buffy and Angel are like peanut butter and chocolate if peanut butter were to turn into an evil killing machine when it was inserted into chocolate. Man, that is a bizarre comparison. Anyhoo, the Buffy and Angel relationship was the perfect tortured forbidden love story and in the hands of SMG and David Boreanaz the characters were fun, sexy, thrilling and heart breaking depending on the episode you were watching.
Even when Angel’s curse was broken and he became Angelus there was an intense chemistry between him and Buffy that dwarfed any of the other relationships Buffy or Angel entered into. From the first moment they met it was pretty obvious that Buffy and Angel were end game for this franchise and I imagine that somewhere out there in the fictional Buffyverse that the Vampire Slayer and the Vampire with A Soul have found their way back to one another and are living happily ever after with a future full of “fat grandchildren” waiting for them.