Imperiex wins against weak Galactuses, we can at least give him that. Then again, Galan can use the UN to kick his ass at any time, but thats sketchy so we will try not to use it.
A strong Galactus wins this battle, he has the ability to absorb all cosmos, time and space and within his power set has owned the Celestials.
And yes, this thread has been done to dead and it should be closed.