I am very saddened by this news. I have enjoyed so many of his film scores and concert works. I join other posters above in highly recommending PAN TADEUSZ. There is also an excellent CD of four concert works on Olympia OCD 308, which includes ANGELUS, a huge-sounding work for mixed choir and orchestra that is alternately terrifying and beyond beautiful. (Avoid the pale, lackluster Naxos CD of this piece.)
A bit of trivia: Kilar wrote the fanfare played at the inauguration of Pope John Paul II. This was available on a Crystal LP.