I personally like the Energon Megs design... sorta an SR-71 from hell. Works for me. Personally tho, I think Megs should be a triplechanger tank/jet. I personally hope the movie Megatron personality is nothing like the G1 personality. I recently watched the first season, and Megatron was annoying and stupid. I much prefer the later incarnations of Megatron where he's actually a strategist and actually does evil, rather than just laugh maniacally and whimper when the Autobots shoot at him once.
I realize the one and only point to the Transformers is to sell toys, but at least give us a Megatron with the castiron manifolds to wreck havok on the population of earth.