Beethoven and Mozart are so famous because they were so damn good. From my small amount of experience they were better than most other composers. (Not to say that the others weren't good) Beethoven is famous, and rightly so, because of how revolutionary and creative his stuff was.

Bach is my favorite, though. Handel isn't bad, but alot of his choral stuff is in English and that bothers me. I prefer to not know what is being sung. Haydn is good but I'm unfamilliar with alot of his stuff. I don't know much about those other composers.