The Baroque era is obviously the king era of Organ. I also favor the Baroque's solo violin repertoire. Bach probably wrote the best solo violin music. However, Baroque music can be relatively predictable. The Classical era was good, but it would be so much more boring if it weren't for Mozart. The Classical era brought us Mozart's Requiem in D Minor, which is, in my opinion, the greatest work of this era. I think Mozart was the best orchestral composer, and Beethoven was the best piano music composer. The Romantic era definitely really brought out some virtuosity. Chopin and Liszt in particular. I think the Romantic era is the king in terms of piano music. With composers like Liszt, Chopin, Alkan, etc. in the Romantic era, I think the piano not only brought emotional characterization to a high level, but also virtuosity. The impressionist era will always be my favorite, though. This is when there really weren't "rules" to music. Debussy is my favorite composer, and he had unique and creative (although sometimes crazy to musical conservatives) styles to his composing. His use of orchestration and harmony is something that not many people did after Debussy, mainly because it was so "his thing". But I connect better with the harmonies and composition in this era more than any. As for the modern composers, I love Prokofiev, however I hate the composers who overdo the diminished and dissonant music like Sorabji. I find it very cheap composing only dedicated to musical difficulty.