I confess to having a soft spot for Salamence. He looks cool, I found I could make a good moveset for him (mine knows Dragon Claw, Crunch, Fly and Zen Headbutt), with Noivern and Haxorus coming in second. I heard that Dragalge's typing can really help him out, and Altaria is a good defender (especially with Dragon Dance). I'd say those are probably the best ones.