Theists actually have all the proof they need.
Let's think of it in the terms of history and logic. In the past, even around Columbus' time, many people still believed that the earth was flat. It took logic, such as the shadow of the earth on the moon during an eclipse, the way ships seem to slowly disappear from the horizon the farther they are from a point of view, and the ability of explorers such as Columbus and Magellan to sail without falling off the "edge" of the earth. Now would they have solid proof of the roundness of the earth if they weren't open to the idea? If everyone was so closed to the idea of a flat earth, we would all still believe the earth is flat today. It took the faith of sailors to prove the earth's curvature. After Magellan was able to sail around the world without falling off, it was pretty much a done deal that the earth was round.
Now let's get back to religion. Atheists do not want to believe in God because "there is no solid evidence." But are they too positive that there isn't a God that they just do not want to try to search for him? The way to prove theories is to experiment, and ONLY when the experiment is done is there actual evidence that theory may be correct.
Jeremiah 29:13 says "You will seek me and find me, when you seek me with all your heart."
The only reason atheists do not have the "proof" that God exists is because they don't even try to look for Him. I, on the other hand, am a Born Again Christian, and I know for a fact that God exists, because I actually had the guts to look for Him. I found Him.
Concerning other debates I've seen:
"God allowed slavery. Do you really want to have a God who accepted such immorality?"
Well, think of it this way. The Old Testament did, in fact, showcase people who had slaves. This is the Old Testament. Keep that in mind. Now, this was when God tried communicating with us, humans, before sending his son, Jesus, to save us. Do you really think we, humans, who are not NEARLY as intelligent as a Godly figure, can understand or interpret the message He was trying to tell us? It's like this. If I were to talk to a cockroach and say, "Leave my house, I don't want you here," do you actually think it would obey? No, of course not, because it doesn't understand me. It's the same situation as God trying to communicate with us. God sends his only son to earth, thus the beginning of the New Testament. Everything Jesus said and did was supposed to explain what God wanted. Jesus did not advocate slavery. People who say that God advocated slavery simply just misinterpreted Him.
"God did not want nations to mix, so the KKK in correct. The Bible clearly states that Miriam and Aaron spoke against Moses for marrying an Ethiopian woman."
God did not intend for humans to misinterpret this either. People say that this verse of the Bible tells us not to mix nations, thus advocating racism. That is surely not the case and is a strong example of misinterpretation. First of all, God was very proud of Moses. That is why He made him the leader of all those who left Egypt. Secondly, Miriam and Aaron are NOT God. Just because the Bible said they got mad at Moses doesn't mean God was too. It is also made clear in the New Testament that God only commanded believers not to marry unbelievers. So… Don't be racist just because you THINK the Bible had commanded you to be. In fact, the Bible said to love everyone just as you love yourself.
"If it takes religion to make you a moral person, then that is sad because that must mean you are not a moral person after all."
So many people tell theists that the only reason they act "good" is because of their religion, so in reality they should be ashamed because their own mind cannot come up with morals and they depend on a God to make it up for them. Well, this is where you should think to yourself. Ask yourself questions like "Have I ever lied before?" "Have I ever stolen?" "Have I ever looked at people with lust?" "Have I ever been jealous?" "Have I ever wished for bad things to happen to a person?" "Have I ever cursed?" "Have I ever been disrespectful?" For all people, DON'T LIE! You know that you fall under most or even all of these categories of sinners. Truth is, NO ONE is perfect. No one truly is moral. Even if we told the person we wronged that we were sorry, chances are we commit the same sin again and again, even to other people. It continues. No one is "good." So if atheists tell theists that "they are not moral because they need God to help them be good people," then they are right. But before they are quick to judge us, they must ask themselves, "Am I good?"
In the end, this is my statement. I believe in God because He has brought me through so much pain. To be honest, most the pain happened when I wasn't in this "religious mood." I've witnessed many miracles. I've seen people change dramatically because of repentance. I've seen people die happy because they believe in God. I have seen them smile through the worst situations because they've given their problems to God. I've seen that God exists because of the goodness I've seen in people. People act as testimonies, and that's proof enough. People are able to see the future because the Bible said that there would be many prophets. The Bible said that "Mothers would give birth to monsters" which explains the generations that are becoming worse and worse. The Bible said that there would be false gods, which explains the claims of men who believe they're Jesus. The Bible has been correct in everything, including things predicted in the future. Pretty impressive right? Considering it was written about 2000 years ago. Now let me ask: How many times were science textbooks updated? Would you really put your trust in a book that "ALWAYS" changes its content because somehow it was proven wrong? Or would you put your trust in a book that doesn't need to be updated because it was and always will be right?