reasons to believe, there is no God

[Tiberius]

the cosmological argument does not elucidate WHICH GOD might be the designer of the universe, but that a designer, a intelligent creator, is the best and most rational answer to the question of the cause of our cosmos.

No it doesn't. The cosmological argument establishes the existence of a first cause. Only by extension can this be used to somehow demonstrate a God existing, but it fails miserably to do this. The cosmological argument is this:

1) Every finite and contingent being has a cause.
2) Nothing finite and contingent can cause itself.
3) A causal chain cannot be of infinite length.
4) Therefore, a First Cause (or something that is not an effect) must exist.

See? No mention of God. The argument may be logically sound, but when you put this in the context of reality, it doesn't pan out in the same way. In quantum mechanics, you get uncaused events all the time, and if the Big Bang theory is true, the question "what caused the Universe" is a nonsensical question, because the Big Bang was the start of time, and causal chains only exist when there is time. Thus asking "what caused the Big Bang" is a non question.

The existence of God to be the first cause also forms several problems with the argument, especially the "causal chain cannot be of infinite length" part. Let me demonstrate:

If we can agree that a causal chain is a chain of cause and effect, cause and effect, then we must also agree that an infinitely long chain of cause and effect is either a chain that has an infinite number of causes and effects, or a chain that has an initial infinitely long cause, followed by a finite event, finite cause, etc, etc.

In other words, even with a first cause, you can get an infinitely long chain of causal events, if and only if the first cause is infinitely long (since by the time the first "event" takes place, an infinite amount of time has already taken place). God is said to be such a being, existing eternally, with no beginning, thus if God is the first cause, he is the start of an infinitely long causal chain (and thus contradicts 3).

If we take God as the first cause, yet say that he is not eternal, or not infinite, then this begs the question "what caused God?". If there is nothing to cause God, then it is perfectly possible that this God does not exist, and that nothing caused the universe to be. To argue otherwise would be to put special privileges on God in order to make the argument fit around him, rather than seeing that there is an alternative explanation that does not involve infinitely complex beings to exist.