At the moment I have 6 on the go.
The bible where I read two pages everyday,
a self-improvement book (one chapter a day),
a financial book (one chapter a day),
a teen book (one chapter a day, this is so I can discuss reading with my kids),
a Biography (also 1 chapter a day)
and of course a novel (which I read until I fall asleep).
I try never to read more than one book from the same genre.