According the me the most romantic scene the Indian film industry has ever protrayed is the Sholay scene where Jai sits playing the mouth organ on the patio and Radha goes around the balcony dimming all the lanterns, and casually exchanging glances.
aradhana with the great Rajesh Khanna is the best romantic movie todate and so is Sangam the Raj Kapoor, Vyjanthi mala and Rajendra Kumar combinations.