Some of us musical snobs like to say we like Tchaikovsky's neglected Second Piano Concerto more than his ever-popular First. Last night in the Kennedy Center Concert Hall pianist Bella Davidovich, conductor Mstislav Rostropovich and the National Symphony Orchestra gave us ample grounds for such enthusiasm.

The concerto was the final (and best-known) work in a program devoted entirely to unfamiliar music. Least familiar of all was "The Pied Piper" Overture by Stephen Douglas Burton, which was having its world premiere, and somewhere in between was the "London" Symphony (No. 2) of Ralph Vaughan Williams--conductor Rostropovich's first performance of this composer. All three works are crowd-pleasers, and all got rousing performances--though the Burton and Vaughan Williams works should sound even better by the end of the week's concerts. The Tchaikovsky won a well-earned standing ovation.

Burton's "Pied Piper" Overture offers 10 minutes of pure brightness for orchestras that want to play something new without scaring the audience. It bubbles with melodies--some adapted from a children's opera of the same name that Burton is preparing for Wolf Trap, and a flute piece on the same subject that he is composing for Jean-Pierre Rampal. The orchestration is a riot of deftly applied colors, with plenty of good solo material for orchestra members, a big, romantic melody for the strings, and lots of idiophonic percussion.

The first encounter of Rostropovich and Vaughan Williams proved to be a very promising one. In many passages, the Russian conductor's interpretation is a shade more colorful than what is usually heard from British conductors--but, on the whole, the music seems to benefit from this approach. With greater familiarity, Rostropovich may become a bit smoother in some transitions, and perhaps he will be able to alleviate the music's longueurs--but these seem to be built-in and there are limits to what can be done with them. Fortunately, the music also has a lot of color, which was beautifully brought out and perhaps even enhanced by a slight Russian accent. Rostropovich should be particularly commended for his perception and adumbration of the British folk flavor that permeates the music.