In the Transformers movies, cartoons and comics Optimus Prime is always called upon to save the day from a ruthless enemy. Transformers 3 spoiler alert. In the third movie Optimus Primes' main nemesis Megatron is killed off once again leaving the way clear for another opponent to clash big metal fists with him. As there will no doubt be more Transformers films which of the Decepticons has the necessary strength and cunning to go up againts the Autobots.

The most obvious solution is to add Galvatron to the mix. Galvatron first appeared in the 1985 Animated Transformers movie and was made out of the dying Megatron by the planet sized transformer Unicron. Galvatron is very similar to Megatron in personality. He's a maniac who hates the Autobots and wants planet and galaxy domination. He also comes in purple.

Scourge is another Decepticon that was remade by Unicron out of the remains of a fallen Decepticon named Skywarp. As he was not featured in the movies so far Scourge could be made out of the remains of Starscream. Or Scourge and Galvatron could be characters in their own right which would allow Megatron and Starscream to be brought back in later movies.

Unicron has being mentioned many times by Transformers fans as someone who would make a good villain. I'm not sure. While Unicron is undoutedly incredibly cool his scale would make him a big problem. Although, having a live action planet sized transformer on the big screen would be something spectacular to witness.

My favourite main villain for future Transformers movies would be the Dinobots led by the mighty Grimlock. Although the Dinobots are Autobots they are not the smartest of bots. They could easily be played off against the Autobots by either a Decepticon or a human. How would they make sense in the context of a modern set film? Simple. The Dinobots could have crashed to Earth millions of years ago taken on Dinosaur forms and then their ship gets damaged and covered up in the meteor storm that wipes out the dinosaurs. The Dinobots can be uncovered much the way real dinosaurs are. That said the writers have used the 'Transformers have been here for years' slant in all three movies now so it might be time for new ideas.

What about a brand new character created for the film? This could be a way to go. New Transformers characters are few and far between but that is generally due to the popularity of the classic cast.