I'd say He-Man, obviously, at the head of any group. Then Fisto, because for sheer power he comes second only to He-Man. I'd have Man-At-Arms for the brainpower, Teela because she's the best warrior (and she's hot! ). I'm not sure about the last one. It would either be Ram-Man or Man-E-Faces.
(I'd also choose Battle-Cat, but I'm going to cheat slightly and count him as one with He-Man ).