I inhale books. While I don't have a strict schedule of how many books, I usually get through a book or two in a week (depending on work and other factors). I used to read more, but I'm comfortable with teh choices I made.
Learning new and different things improves your ability to learn and improves your mental capacities. And its quite fun. You'll find hte compendium of human knowledge in books and, increasingly, on the Interwebs.
Other benefits include improved vocabulary, more ideas, more
mental models, better ability to express yourself, etc. Lots of great stuff.