You seem to only be talking about popular culture, in which case Norse mythology is probably more influential. When considering ancient mythology or even modern day religions, though, I'd say that the ideology behind them and the significance of the moral lessons that they teach are far more important than the actual stories, characters and deities, which are hailed by popular culture. It's not, for example, supposed to be a fun story about a viking god who throws his eye in a well, but rather, you're supposed to see the significance of sacrificing important things to gain wisdom. Therefore, when you're considering influence, it would be best not to count the number of movies made on Greek gods, but rather to see what ideas that Greek mythology suggested that are still accepted today.
Not by any analysis or other scholarly means, but just by intuition, I'd probably say that Egyptian mythology would outrank most well-known mythologies as far as influence is concerned simply by predating them. That's because they all are very similar in more than one sense and the earliest religions probably influenced everything that followed anyhow.
“These are my principles; if you don’t like them, I have others.” – Groucho Marx
