Believe it or not, I was discussing this the other day. My opinion is yes, zero is not, as some insist, a non-number. While in math it always affects the outcome of an equation unlike standard numbers, the same could be said for imaginary numbers, pi, and fractions. The symbol "0" represents the absence of numerical counting, but it's as valid as saying "There are no bananas." If there are 0 bananas, there are no bananas to count.
On a tangent, one might consider this theologically. Many consider themselves in a religion that is monotheistic, where you have 1 god. Others are polytheistic, so they believe in 2, 3, or maybe 1000 gods. Then there is the athiest, who says there is no god. For him, there is 0 god. This doesn't mean there is no god in the world, he just hasn't acknowledged any god or gods as his own. (Which raises the question of the difference between atheism and agnosticism, but that's a different post.)
So 0 is a number, just not a number you'd associate with anything but... nothing.
On a tangent, one might consider this theologically. Many consider themselves in a religion that is monotheistic, where you have 1 god. Others are polytheistic, so they believe in 2, 3, or maybe 1000 gods. Then there is the athiest, who says there is no god. For him, there is 0 god. This doesn't mean there is no god in the world, he just hasn't acknowledged any god or gods as his own. (Which raises the question of the difference between atheism and agnosticism, but that's a different post.)
So 0 is a number, just not a number you'd associate with anything but... nothing.