I heard that there are 7 versions of Devdas. But I only know of 4 of them. What are the others?

The 4 I know of are:

1. The first old b/w...not sure of director or star.
2. The version with Dilip Kumar...I think directed by Bimal Roy
3. Maqaddar Ka Sikandar starring Amitabh B...not sure of the director.
4. The New one...with SRK directed by Sanjay Leela Bhansali

Out of those you've seen which one(s) are the best and why?

I've only seen the 2nd & 3rd so I can't really give a deep opinion...I think they're both as good as each other.