There are not many G1 characters I'm holding out for in the MP line now. The '86 movie cast (Springer, Arcee, Galvatron, Cyclonus, Scourge, etc), Blaster and his cassettes, a cartoon accurate Bumblebee, and Jazz.
However, I'd really like to get a full set of the season 1 Beast Wars characters in the MP line. That's what I'm really interested in getting now.