As far as whether there is a "first cause," some of the debate hinges on the following question, often brought up on these boards (and elsewhere): "if God can be eternal, then why not just say the world is eternal?" It's a good and fair question. But what exactly is the target of this question? The aim is to be able to say that there is no need to call upon a God to explain the existence of the world; that the world itself can be eternal. As I have said in the past, however, this is only a rebuttal for a cosmological argument that uses the premise "the world had a beginning." There are really quite a few different arguments. Here's one that I've talked about in other posts (very quickly sketched out):
1. If X is contingent then it is possible that X not exist.
2. Anything existing contingently has a cause or reason for its existence--there is an explanation for why it exists rather than not.
3. If everything exists contingently, then there is no ultimate explanation for why anything exists.
4. Hence, there must be something that necessarily exists (not contingently) that ultimately explains the existence of everything contingent.
As I said, this is quick. But it makes no difference whether or not there is an infinite chain of contingent causes that make up the world. Let's say the world is eternal: no beginning, no end. The series itself still would need an explanation for its existence. If there were no explanation for the existence of the series, this would be just as strange as if the only extant thing in the world were a teapot, and it existed for absolutely no reason.
There are plenty of ways to criticize this argument. But I still like it.
Not every objection can be adequately answered, I think. But that doesn't mean that someone can't find it compelling. Which I sometimes do.