Very Good Topic IMO
1.Rajkumar Hirani (3I has an IMDB rating of 8.2,many hollywood studios are planning to remake it)
2.Shankar (He knows how to make a good big budget movie..Shivaji,Robot were both entertaining yet good films)
3.Rahul Dholakia (My personal fav.I love his way of film making.Parzania and Lamhaa were both fab,especially the former)
Special Mention-Rohit Shetty.Dude can definitely work wonders with something like the fast and furious series or the transformers series!