I think this calls for a definition of 'evil'.
Is an earthquake 'evil'?
Is a war evil, but we are the ones resposible for it?
I believe (from analogy) that God is not omnipotent. The basis of my view is that nothing that I have seen or believe to ever exist in nature is all powerful. Therefore to assume that ANYTHING out there is omnipotent is a tad absurd.
Then again, people would question whether our Creator is a "God" if she isn't omnipotent.
I'd like to say: Yes!
I too can conceive of a non-omnipotent God. Whoever made that a definition? I think it hasn't always been. Maybe God, or the Gods, are just a lot more powerful than we are.