Although he has instances that prove otherwise, for the most part I consider Bach a "cool" mathmatical (and theoretical) composer.
Now, different instances would be his violin partitas, and double concerto.
These are phenominal, and beautiful. I think that he is good, but I prefer romantic music.
Some of his works really do sound similar.
The WTC is excellent, and has its moments, but it just doesn't cut it emotionally for me.
By the way, I think that Mozart is considered the most popular composer, followed by Beethoven, and then Bach, but I might be incorrect.
Beethoven was HUGE because he wrote not only so much solo piano, but famous symphonies, piano trios, etc.