I was in a similar position a while ago. I was (actually, still am) obscessed with Rachmaninoff's music; but my teacher told me I had to learn more Bach. Needless to say, I wasn't thrilled about it-Bach seemed so boring to me. At first, my practicing only seemed to reinforce that opinion, but gradually, I got caught up in the wonderful mixtures of melody that make up so much of Bach's music. Any of his fugues, for example, give a fun challenge. Try to find each possible voice, and bring it out; occasionally bringing one to the fore, occasionally another; it adds a richness to the music that I simply didn't appreciate before. Learning to "sing" with Bach's music will aid your tonal control, and ability to bring out counterpoint. These characteristics are valuable in all music; I found them especially useful in being able to hear all the voices in Romantic (Chopin, Liszt, etc.) music, and not just the main one. It can add depth to your playing of music of all periods.