The 1st appearance of Magneto is definitely a book to get................as it features the 1st appearance of the X-Men as well. (thumbs u
My point was that if you are chasing movie related 1st apps of villains or lesser characters the time to buy is well before the movie hype starts in earnest. The time to chase them is when a film is rumored/announced by the big two, not after it has been cast or is in production. Buy early and at low prices, flip at the peak, and even if you are stuck with a copy or two you will still be able to move them at a higher price than you accumulated them at.
The real time to buy them is to already have them.