You're right. There's no way to disprove God. Just as there's no way to disprove that our entire universe isn't a speck on a flower being protected by an elephant named Horton.
There are countless zany beliefs that can't be disproven. Therefore we can't rule out Zeus, or Ra the sun god, or Shiva, or *gasp* Allah.
Hey maybe the Jonestown people were right and right now they're on some ascended plane with aliens like they believed! You can't disprove that!
To Possibilities!
And to the AWESOME Monkey job of deciding what's plausible!