Most people take up Mozart as they get older and wise. The Beethoven symphonies are still great in a good performance. The 3rd (Eroica) might be the best of all time.
But as a music teacher of mine in college said, Mozart was primarily a composer of opera, and even his symphonies sound as if there should be words attached to the themes.
If I were on a desert island and had to choose the complete works of three composers to take along, it would be Bach, Beethoven and Chopin. If I could bring five, I would add Haydn (his choral music, IMO, is brilliant) and Schubert.
Who would be the 3 or 5 you would bring along?