The thing is, we only see the real Damon when he is around Bonnie. We see Damon at his best...and I don't mean this as a put down on any other ship at all. Its just how I see it.
When Damon is with Bonnie, he is the very best that Damon can be. He's charming, witty, measured, he respects her, he appreciates...he's not insecure acting off of emotion. He's simply Damon. And on the same token, he's not a psycho-path when he's around Bonnie either...
so the way I see it Bonnie=best choice for Damon.
but I'm a Bamonator so I may just be a little, teeny bit bias
ETA: You're welcome everyone