yeah the caffeine definitely hampers it. I quit drinking so much coffee but I still drink a lot of black tea. The days when I drink less caffeine or none at all there is a marked improvement in sleep patterns.
I'd consider myself a night person but I have noticed that when I do wake up earlier I have more focused energy. My night energy is abundant but very unfocused (I am currently browsing these forums instead of working on a school paper, go figure).