my top ten in no particular order:

1. E-Flat (Ghatak)
2. The Music Room (Ray)
3. Mr Shome (Mrinal Sen)
4. Om Dar-b-Dar (Kamal Swaroop)
5. Our Daily Bread (Mani Kaul)
6. Hot winds (M. S. Sathyu)
7. 36 Chowringhee Lane (Aparna Sen...everything else she made is bogus!)
8. Monologue (Adoor Gopalakrishnan)
9. Seventh Horse of the Sun (Shyam Benegal)
10. Pyasa (Guru Dutt)

One film that almost made it to the list is "The Adventures of Goopy and Bagha", a fantasy by Ray. Taken from a story by Ray's grandfather, this is Ray at his best in all departments, not the least being music. The subtitles do not do justice, but go ahead and see this anyway!
Other strong recommendations are: "Who Pays the Piper" (Kundan Shah), "Pestonjee" (Vijaya Mehta), "Time Addiction" (Amitabh Chakraborthi), "The Chess Players" (Ray), "Titas, the Name of a River" (Ghatak). There are many many more actually!