Theists: What is the most compelling argument you have heard for Atheism?

[SteveII]

Physicists posit a multiverse for the express reason to overcome the odds of getting the constants we have? Are you saying they are wrong?

This is yet another misrepresentation.  Physicists originally proposed the multiverse as an implication of Alan Guth's work on inflation.  It's a canard that the multiverse theory was originated to solve the fine tuning problem.

"It's hard to build models of inflation that don't lead to a multiverse," Alan Guth, an MIT theoretical physicist unaffiliated with the new study, said during a news conference Monday. "It's not impossible, so I think there's still certainly research that needs to be done. But most models of inflation do lead to a multiverse, and evidence for inflation will be pushing us in the direction of taking [the idea of a] multiverse seriously."

Other researchers agreed on the link between inflation and the multiverse.

"In most of the models of inflation, if inflation is there, then the multiverse is there," Stanford University theoretical physicist Andrei Linde, who wasn't involved in the new study, said at the same news conference. "It's possible to invent models of inflation that do not allow [a] multiverse, but it's difficult. Every experiment that brings better credence to inflationary theory brings us much closer to hints that the multiverse is real."

http://www.space.com/25100-multiverse-co...waves.html

I will respond to your other comments later, but I researched this one first: You are correct and I am wrong. The multiverse was first hypothesized as part of inflationary theory.  The concept has been used quite a bit to explain away the fine-tuning of our universe.