This should have been originally a question for a poll but then I have realized that there have been as many great composers as not possible to make any list with no name missing. Thus, I put down my beloved ones:
1. Bach, Mozart, Beethoven
Bach tells us via his music calmly: do not be afraid, everything is ok, every thing and being has its right place and function in our great world, we all have a deep sense not forgotten, so let us joy.
Mozart brings us the melodies of Heavens singing: do not be scared, although sometimes things are not as we would like to have them, let us joy.
Beethoven warns: things are getting bad often but do not be frightened, if strong and heroic enough we can cope with any tragedy and joy as well.
They all raise our spirits to God.
2. Russians: Cajkovskij, Prokofiev, Mussorgskij, Stravinskij, Sostakovic, Rachmaninov ...
As the whole art come from Russia, they brought the music of extraordinary depth, width, heighth and fullness of human emotions; not hidden behind the curtain of any style.
3. Others including Monteverdi, Vivaldi, Chopin, Schubert, Dvorak, Smetana, Verdi, Gershwin, Gorecki, Ellington and many many others ..... whose works I was lucky to hear and enjoy.