Probably flying type, most of my favorites are more or less associated with it
A team of Farfetch'd, Beedrill (yeah, not flying, but whatever, the E4 always do that kinda stuff. And hey, at least it can fly), Jumpluff (Usually I prefer 'saur here, but that thing is not even close to being a Flying type), Scyther and Gyarados would probably not exactly be the strongest, but it would be awesome.
Speaking of which, I'll have to do a run with such a team at some point. The only problem is going to be having Magikarp (I mean, what else could be my signature mon?) as a starter, I'll have to set the level to 15 or this will be impossible.