Okay, let's try, my top 25:

1 Handel

2 Mozart

3 Tchaikovsky

4 Haydn

5 Puccini

6 Sibelius

7 Verdi

8 Dvorak

9 Brahms

10 Janacek

11 Mussorgsky

12 Rameau

13 Rossini

14 Mahler

15 Beethoven

16 Britten

17 Schubert

18 Wagner

19 Schumann

20 Bruckner

21 Bach

22 Strauss (R)

23 Monteverdi

24 Prokofiev

25 Bellini