Wolfgang Amadeus Mozart (1756 - 1791) was an Austrian classical composer and pianist who composed a huge number of works for orchestra, piano and many concertos for other instruments as well as Opera.
Mozart wrote 41 symphonies so it is a little difficult to pick a favourite but I decided on his last one The Jupiter in C. The link is to the whole work being played by the London Mozart Players. The track below is of just the Menuetto. Allegretto and is performed by the Vienna Philharmonic conducted by Leonard Bernstein.
He wrote 27 piano concertos and my favourite is his 23rd in A Major which the link will take you to Maurizio Pollini as the soloist again playing with the Vienna Philharmonic.
If there were only one classical composer in the world then Mozart wrote enough to satisfy everyone. The Requiem was his final composition but he died before he could complete it at the age of 35. Salieri and Süssmayr are thought to have completed his Requiem after his death.
Mozart's discography can be found here.