Just for an easy post that isn't totally random, I'll give the five people who have had the greatest impact on my theology so far. My list doesn't necessarily include just theologians, but others whose thoughts I have integrated into my worldview that has as a result affected my theology. Also, it isn't necessarily those who I agree with the most, but those who influenced me the most through my interaction with them.
My top 5:
1) John Wesley - Could you expect anything less from me? Admittedly, his theology isn't the most developed, nor do I agree with him on every point, but I find much of his theology to be a proper framework to build from (I did find the details of his theology are often amiss). Especially important to me is what I would call his preliminary understanding of a Christian psychology, and not as much his soteriology (though I still find it very useful to begin from).
2) Karl Barth - Yeah, I poke fun at the obsession that some to have with him but after Wesley he has most influenced my way of thinking. His influence on me isn't in the large amount of his teachings that I have gleaned only from his Dogmatics in Outline, but the one teaching he is the most well known for: the Christ is the revelation of God. This one idea, though I don't take it to where Barth does, is the one idea that has influenced my idea about Christ, His purpose, and God more than anyone else.
3) Jacob Arminius - I haven't particularly read much from the guy, but any person that is a Protestant and does not believe in predestination likely has his roots in Arminius's dissension against the Reformed teachings. This is especially true for any person who believes a person can fall from grace, like I can.
4) Soren Kierkegaard - His concept of the leap of faith has greatly influenced me. His affect on me is really more in the area of epistemology (though that is not what he is known for) and psychology, but since those are so influential in my theology, he has to be towards the top of my list.
5) William James - The American psychology was not particularly religious, but he wrote a book on religious experiences. The one concept that most influenced me was the idea that religious emotions are not distinctly different from other emotions, but that they are merely emotions experienced in the context of religion. May not seem like a profound concept, but in Protestant theology and the concept of Total Depravity (which I held to at one time), there is a tendency to separate religious emotions and convictions as altogether distinctly different from non-religious emotions and convictions. While it might seem like a minor point also, it has profound affect on the way one sees humanity and its relation to God.
Some influence but not on the top 5 (not in any particular order):
Rudolf Bultmann - While I don't go to his extreme, as a result of him, I see a distinction between subjective and objective elements of religion
NT Wright - He introduced me to a covenant outlook and influenced how I saw covenants, though I disagree with his idea of covenant faithfulness being talked about in the letter to the Romans. Covenant is a good framework to understand the Bible, though I find it lacking it as a pivotal and a very explicit part of the New Testament.
Carl Jung - The concept of archetypes (and not his teachings per se) allowed me to speculate that humanity has an "ideal man" archetype that we can not fulfill without the revelation of Christ to show us how to be the "ideal man"
Thomas Kuhn - The idea of "paradigm shifts" made me a self-skeptic and also got me thinking into the idea of how do we know (epistemology).
John Calvin - Technically, one should include Theodore Beza also, because by encountering TULIP and studying the topic, I have come to reject it thoroughly. Without that, I may be a more of a moderate in the Calvinism/Arminianism area.
The Orthodox Church - I struggle to pin point an exact theologian in this church, but the idea that the effects of the sin of Adam was not a inbred sinfulness or a inherited guilt, but an environment of death influenced my concept of original sin and the sinfulness of humanity.
Sigmund Freud - Throw out everything but the concept of the unconscious and subconscious. But that idea has influenced how I see the flesh when it is seen in contrast to the Spirit. But let it be said that Freud's idea of unconscious do not directly correlate with the flesh, nor that Freud was the first person to speak of the unconscious and subconscious.
Nowhere near to the top:
Paul Tillich - Interesting writer but his ideas are so obscure that they will never be of any value in my opinion.
Augustine - One might say through John Calvin I was influenced by him, but I never interacted much with his works and was affected by it. Nor did I inherit many teachings from him like Arminius who I did not interact much with. Honestly, while his theology isn't all bad in my opinion, I find many of the major problems in Western theology is due to his influence.
Anselm - Like Augustine. I never interacted much with his works and affected by it. The major problems with Western theology that I can not attribute to Augustine, I attribute to Anselm and his atonement theory of satisfaction theory, from which came penal substitution theory and other atonement theories centered upon legal concepts that I find hamper Western theology.
Norman Geisler - I own his systematic theology books, hence his being on this list though he really isn't a theological heavy weight. He is a standard conservative evangelical: strong in their ethical and moral ideal but weak in theology.