To Presup or not?

I am trying in my own study to decide which perspective of Evangelism is more beneficial. I think most people will agree it depends on the situation but I believe when you formulate a conviction than you will approach a conversation with that conviction. So here is the question I want to ask others what they think. Do we evangelise with Presuppositional apologetics or not? If you are not sure what this is please read on...

(carm.org)
This form of Christian apologetics deals with Presupposition's. A Christian Presuppositionalist presupposes God's existence and argues from that perspective to show the validity of Christian theism. This position also presupposes the truth of the Christian Scriptures and relies on the validity and power of the gospel to change lives (Rom. 1:16). From the scriptures, we see that the unbeliever is sinful in his mind (Rom. 1:18-32) and unable to understand spiritual things (1 Cor. 2:14). This means that no matter how convincing the evidence or good the logic, an unbeliever cannot come to the faith because his fallen nature will distort how he perceives the truth. The only thing that can ultimately change him is regeneration. To this end, the presuppositionalist seeks to change a person's presuppositions to be in conformity with biblical revelation.
I have found that a person's presuppositions are extremely important when discussing God and the validity of Christianity. I always ask diagnostic questions to find out where a person is philosophically and presuppositionally so I might better discuss Christianity. This is a very important point to focus on because one's presuppositions will govern how one interprets facts. Please consider the following dialogue as a realistic example of how this works.
Allen: I am an atheist and evolutionist. Prove to me there is a God.
Paul: I do not think I can do that, because of your presuppositions.
Allen: Why not?
Paul: Because your presuppositions will not allow you to examine without bias the evidence that I present to you for God's existence.
Allen: That is because there is no evidence for God's existence.
Paul: See? There you go. You just confirmed what I was stating.
Allen: How so?
Paul: Your presupposition is that there is no God; therefore, no matter what I might present to you to show His existence, you must interpret it in a manner consistent with your presupposition: namely, that there is no God. If I were to have a video tape of God coming down from heaven, you'd say it was a special effect. If I had a thousand eye-witnesses saying they saw Him, you'd say it was mass-hysteria. If I had Old Testament prophecies fulfilled in the New Testament, you'd say they were forged, dated incorrectly, or not real prophecies. So, I cannot prove anything to you since your presupposition won't allow it. It is limited.
Allen: It is not limited.
Paul: Yes it is. Your presupposition cannot allow you to rightly determine God's existence from evidence -- providing that there were factual proofs of His existence. Don't you see? If I DID have incontrovertible proof, your presupposition would force you to interpret the facts consistently with your presupposition and you would not be able to see the proof.
Allen: I see your point, but I am open to being persuaded, if you can.
Paul: Then, I must ask you, what kind of evidence would you accept that would prove God's existence? I must see what your presuppositions are and work either with them or against them.
Presuppositional apologetics differs from Classical apologetics "in that presuppositional apologetics rejects the validity of traditional proofs for the existence of God." A pure presuppositionalist tackles the worldview of a person and seeks to change the very foundation of how a person perceives facts.
Adherents to this position have been Cornelius Van Til, Abraham Kuyper, Greg Bahnsen, John Frame, etc.
(End Quote)
Now the non Presuppositionalist will attempt to spend some time on proving the existence of God and debate evolution, polytheism, etc.

Now the two sides of the coin for me would be someone like Mark Spence (The Dean of the School of Biblical Evangelism) says that he is not a presup and that he finds that the Holy Spirit's job is to convict the world of sin, judgment and righteousness. The longer he is off track on trying to convince someone of God without "presupposing" God the less work is being done on conviction with the power of God.

On the other side we have someone like James White who quotes (and debates) people like Richard Dawkins, and other militant atheist and he says that it is impossible in today's climate not to be a Presuppositionalist in evangelism.

Now I know we can have both, I know we need a good mixture but what do you think is the best way to go about it? Do we spend much time on apologetics to boost our credibility and than use the law and the cross to share the gospel. Or do we use little apologetics and preach the gospel regardless of there opinion??