I've been doing a lot of reading lately on the "morning" vs "any other time" cardio debate. I do my cardio in the morning only because it's most convenient, and because I have no choice if I'm going to be riding my bike to work. That said, I was interested in knowing if there really is any benefit to the time of day you do it.
I'm still not completely sold on one way or the other, and I have no intentions of changing up my routine anyway. However, this is by far the most informative and fairly unbiased article on the subject I've read.