The number of stars you see would, of course, depend on how bright your surrounding area is and how good your eye-sight is.. But under ideal dark sky conditions, around 10,000 can be seen in both hemispheres.
Sources:
Lisle, Jason. Taking Back Astronomy. Green Forest, AR: Master, 2006. Print.
http://science.intellichristian.com/how-many-stars-can-be-seen-with-an-unaided-eye