Unfortunately, there is no definitive Superman. There are plenty to choose from though.
>>8318867If you want a Fleischer Supes, go with this anon’s suggestion.
If you want a Golden Age look, there’s a DC Direct First Appearance figure.
If you’re into the Chris Reeve version, the middle one in my pic is NECA. It looks great, but the articulation isn’t amazing. There’s also a Mezco coming later this year.
The one I’d suggest as an all-around great figure is the one to the left of Reeve. He’s a DC Direct from a line of Supes figures from the early 2000s. He’s got a great classic likeness and color, and at the time boasted a whopping 21 PoA. They’ve rereleased him a couple times since in different packaging.
Hope that helps, OP.
