The Pew Forum on Religion and Public Life conducts the US Religious Landscape Survey. The second report in this survey tells us that:

Among atheists, 21% believe in God; 12% believe that God is an impersonal force; and 6% believe that God is personal.

Among atheists, 12% believe in heaven while 10% believe in hell.

Among atheists, 10% pray at least weekly while 18% meditate at least weekly.

The atheist community appears to have considerable religious diversity.