Not sure of an all time favorite movie but I think Naseeruddin Shah would be one of my all time best actors...
Just happened to see a program on an old movie that NS acted ages back, a film called Masoom. It was the first movie of Shekar Kapur. NS says in an interview says that Shekar Kapur then was a failed actor and he was a friend who agreed to work on the movie to help him out. But was it a help extended to Shekar or NS helped himself.
Jugal Hansraj in that movie fitted the character so well. His innocent eyes helped him to connect with the audience so easily. One of my favorite songs from the movie just takes off showing his pair of eyes. The lyrics and the song was a big hit. I think Gulzar and RD Burman together as a pair was the nicest thing to happen to Hindi cinema.
Check out the song on youtube and I think you`ll agree
http://www.youtube.com/watch?v=MZL_dpb_6Lo
Do nainaa aaur yek kahaanee
thodaa saa baadal
thodaa saa paanee
aaur yek kahaanee
chhotee see do zeelon mein
wo bahatee rahatee hai
koee sune yaa naa sune
kahatee rahatee hai
kuchh likh ke aaur kuchh jubaanee
thodee sai hain jaanee huyee
thodee see nayee
jahaa ruke aansoo
wahee pooree ho gayee
hai to nayee fir bhee hain puraanee
yek khatm ho to
doosaree yaad aa jaatee hai
hothhon pe fir bhoolee huyee
baat aa jaatee hai
do nainon kee hain ye kahaanee