I'm pretty sure St. Thomas Aquinas has to be one of the best (if not the best) people that argue that history has ever seen. The following is five reasons that he says God exists. He starts with something that says that God doesn't exist, then shows why it is incorrect, and proves why he DOES exist. Enjoy! (I know you will, but take your time, and try to understand everything, it gets pretty deep....oh, and this was originally written in Latin, so you can interchange the words "motion" and "change", that may help make the motion part understandable)

"Article 3: Whether God exists.

Furthermore, one should not needlessly multiply elements in an explanation. It seems that we can account for everything we see in this world on the assumption that God does not exist. All natural effects can be traced to natural causes, and all contrived effects can be traced to human reason and will. Thus there is no need to suppose that God exists.

But on the contrary God says, "I am who I am" (Ex. 3:14).

Response: It must be said that God's existence can be proved in five ways. The first and most obvious way is based on the existence of motion. It is certain and in fact evident to our senses that some things in the world are moved. Everything that is moved, however, is moved by something else, for a thing cannot be moved unless that movement is potentially within it. A thing moves something else insofar as it actually exists, for to move something is simply to actualize what is potentially within that thing. Something can be led thus from potentiality to actuality only by something else which is already actualized. For example, a fire, which is actually hot, causes the change or motion whereby wood, which is potentially hot, becomes actually hot. Now it is impossible that something should be potentially and actually the same thing at the same time, although it could be potentially and actually different things. For example, what is actually hot cannot at the same moment be actually cold, although it can be actually hot and potentially cold. Therefore it is impossible that a thing could move itself, for that would involve simultaneously moving and being moved in the same respect. Thus whatever is moved must be moved by something, else, etc. This cannot go on to infinity, however, for if it did there would be no first mover and consequently no other movers, because these other movers are such only insofar as they are moved by a first mover. For example, a stick moves only because it is moved by the hand. Thus it is necessary to proceed back to some prime mover which is moved by nothing else, and this is what everyone means by "God."

The second way is based on the existence of efficient causality. We see in the world around us that there is an order of efficient causes. Nor is it ever found (in fact it is impossible) that something is its own efficient cause. If it were, it would be prior to itself, which is impossible. Nevertheless, the order of efficient causes cannot proceed to infinity, for in any such order the first is cause of the middle (whether one or many) and the middle of the last. Without the cause, the effect does not follow. Thus, if the first cause did not exist, neither would the middle and last causes in the sequence. If, however, there were an infinite regression of efficient causes, there would be no first efficient cause and therefore no middle causes or final effects, which is obviously not the case. Thus it is necessary to posit some first efficient cause, which everyone calls "God."

The third way is based on possibility and necessity. We find that some things can either exist or not exist, for we find them springing up and then disappearing, thus sometimes existing and sometimes not. It is impossible, however, that everything should be such, for what can possibly not exist does not do so at some time. If it is possible for every particular thing not to exist, there must have been a time when nothing at all existed. If this were true, however, then nothing would exist now, for something that does not exist can begin to do so only through something that already exists. If, therefore, there had been a time when nothing existed, then nothing could ever have begun to exist, and thus there would be nothing now, which is clearly false. Therefore all beings cannot be merely possible. There must be one being which is necessary. Any necessary being, however, either has or does not have something else as the cause of its necessity. If the former, then there cannot be an infinite series of such causes, any more than there can be an infinite series of efficient causes, as we have seen. Thus we must to posit the existence of something which is necessary and owes its necessity to no cause outside itself. That is what everyone calls "God."

The fourth way is based on the gradations found in things. We find that things are more or less good, true, noble, etc.; yet when we apply terms like "more" and "less" to things we imply that they are closer to or farther from some maximum. For example, a thing is said to be hotter than something else because it comes closer to that which is hottest. Therefore something exists which is truest, greatest, noblest, and consequently most fully in being; for, as Aristotle says, the truest things are most fully in being. That which is considered greatest in any genus is the cause of everything is that genus, just as fire, the hottest thing, is the cause of all hot things, as Aristotle says. Thus there is something which is the cause of being, goodness, and every other perfection in all things, and we call that something "God."

The fifth way is based on the governance of things. We see that some things lacking cognition, such as natural bodies, work toward an end, as is seen from the fact hat they always (or at least usually) act the same way and not accidentally, but by design. Things without knowledge tend toward a goal, however, only if they are guided in that direction by some knowing, understanding being, as is the case with an arrow and archer. Therefore, there is some intelligent being by whom all natural things are ordered to their end, and we call this being "God."

To the first argument, therefore, it must be said that, as Augustine remarks, "since God is the supreme good he would permit no evil in his works unless he were so omnipotent and good that he could produce good even out of evil."

To the second, it must be said that, since nature works according to a determined end through the direction of some superior agent, whatever is done by nature must be traced back to God as its first cause. in the same way, those things which are done intentionally must be traced back to a higher cause which is neither reason nor human will, for these can change and cease to exist and, as we have seen, all such things must be traced back to some first principle which is unchangeable and necessary, as has been shown."

-Saint Thomas Aquinas

Oh, for a thousand tongues to sing
My great Redeemer’s praise
The glories of my God and King
The triumphs of His grace

My gracious Master and my God
Assist me to proclaim
To spread through all the earth abroad
The honors of Thy name

So come on and sing out
Let our anthem grow loud
There is one great love, Jesus

Jesus, the name that charms our fears
That bids our sorrows cease
‘Tis music in the sinner’s ears
‘Tis life and health and peace

He breaks the power of canceled sin
He sets the prisoner free
His blood can make the foulest clean
His blood availed for me

So come on and sing out
Let our anthem grow loud
There is one great love
There is one great love, Jesus

He speaks and listening to His voice
New life the dead receive
The mournful broken hearts rejoice
The humble poor believe

Glory to God and praise and love
Be ever, ever giv’n
By saints below and saints above
The church in Earth and Heav’n

So come on and sing out
Let our anthem grow loud
There is one great love
There is one great love, Jesus
Jesus

There are so few words
That never grow old
There are so few words
That never grow old
Jesus, Jesus, Jesus

So come on and sing out
Let our anthem grow loud
There is one great love

So come on, So come on
So come on and sing out
Let our anthem grow loud
There is one great love
Oh, there is one great love
Oh, there is one great love, Jesus

-lyrics by David Crowder *Band

"Here we are
Here we are
The broken and used
Mistreated, abused
Here we are

Here You are
Here You are
The beautiful one 
Who came like a Son 
Here You are

So we lift up our voices
We open our hands
To cling to the love 
That we can’t comprehend

Oh, lift up your voices
And lift up your heads
To sing of the love
That has freed us from sin

He is the one 
Who has saved us
He is the one
Who embraced us
He is the one who has come
And is coming again
He’s the remedy

Here we are
Here we are
Bandaged and bruised
Awaiting a cure
Here we are

Here You are
Here You are
Our beautiful King
Bringing relief
Here You are with us

So we lift up our voices
And open our hands
Let go of the things 
That have kept us from Him



He is the one 
Who has saved us
He is the one
Who forgave us
He is the one who has come
And is coming again
He’s the remedy

Oh, I can’t comprehend
I can’t take it all in
Never understand
Such perfect love come
For the broken and beat
For the wounded and weak
Oh, come fall at His feet
He’s the remedy
He’s the remedy

So sing, sing

You are the one 
Who has saved us
You are the one
Who forgave us
You are the one who has come
And is coming again
To make it alright
Oh, to make it alright
You’re the remedy
Oh, in us
You’re the remedy

Let us be the remedy
Let us bring the remedy"
-DC*B, Remedy, from Remedy