My turn 
This list will obviously change with time, but so far of the ones I have seen:

1 Nayak - Satyajit Ray
2 Charulata - Satyajit Ray
3 The Chess Players - Ray
4 Meghe Dhaka Tara - Ghatak
5 Pather Panchali - Satyajit Ray
6 The Music Room - Satyajit Ray
7 Ajantrik - Ghatak
8 Bhuvan Shome - Mrinal Sen
9 Jaane Bhi Do Yaaro - Kundan Shah
10 1947 Earth - Deepa Mehta

The list is rather Bengali-centric...thats because I'm from there. I'd love to see some South Indian films...difficult to access sadly.

Now a best of Satyajit Ray list:
1 Nayak
2 Charulata
3 The Chess Players
4 Pather Panchali
5 The Music Room
6 Devi
7 Teen Kanya
8 Seemabaddha
9 Aparajito
10 Goopy Gyne Bagha Byne

I'm yet to see Kanchenjunga and Aranyer Din Ratri and a few others.

PS. To those who were crying about not having access to Ghatak's films, I have all of them.