Wolfgang Amadeus Mozart (1756-1791) died on this date, not quite having reached the age of thirty-six. I consider this to be perhaps the single most amazing fact in human history. In that short life span, Mozart demonstrated a mastery equal to any other in all the main classical music forms -- opera, sacred music, symphonies, concertos, sonatas, choral -- and I think it is fair to say that in that versatility, he has no equal (even if one might wish to argue that one or another great composer outdid him in one particular form, for example, I would yield to Beethoven on the question of piano sonatas, but Mozart laid a grand foundation for him.)
Today, I suppose, there is no really appropriate piece besides this last work, the Requiem -- with its attendant mystery that we will probably never know which parts are actually the work of another composer. This youtube link gives you the option of listening to the entire Requiem in consecutive order without having to reload. The performance takes about an hour. Anyone not familiar with the Requiem might benefit from obtaining the English translation although basically what you have is the Latin mass in fourteen parts (twelve segments here). Whoever helped out must have risen to a high standard for them, because really it is very difficult to pick out anything "sub-Mozartian" and perhaps it is better not to try.
Remember, we got this entire musical legacy from a man who lived half his allotted life span. Who knows what we missed thereby.
http://www.youtube.com/watch?v=d88xIIRD ... re=related