2. James McAvoy
Appeared in: X-Men film series
When the Fox X-Men film franchise decided to take a trip into the past, it needed a younger actor to portray Charles Xavier in his younger days. For that, James McAvoy was brought in to play the role.
It was a great casting. An underrated one, even. McAvoy is certainly an esteemed actor but he doesn't often get the credit he deserved for his passionate performance as the young Professor X. He did an awesome job, giving us a chance to see what Charles was like in his earlier years, while also featuring little nods and nuances to Stewart's portrayal of the character.
The younger Charles is less reserved than his future self, and that's normal, which allows McAvoy opportunities to make the role his own - something he does very well. The character was quite a different person at this stage of his life but he wasn't completely unrecognizable either - and that's how you know McAvoy did well.
There was more naivety, more vocal passion, and more mistakes; but there was also the growth and knowledge that would evolve him into his older, wiser self. McAvoy delivered and then some, giving us a Charles that was the same, but different.