Atheist means you don't believe in anything. I'm not atheist, but I don't believe in any God.
If you don't believe in any god, or I assume, any higher power for that matter then you're an atheist. You should still have morals, etc.
I'm completely unsure what to believe in. Evolution has it's arguments, and they are quite strong, but I don't believe that there was "a big bang". What existed before that? It can't just suddenly appear. Using this logic, the universe has been here for ever, or there was at least something else, before the "big bang".
Trying to apply taste and philosophy onto empirical science doesn't seem to make too much sense to me. Evolution through natural selection and the Big Bang theory are explanations that currently seem to match our observations. Sure, these theories might just be wrong, but one the of basic principles of science is to try to prove your current theories wrong.