On a thread at the helives blog, I mentioned Arminianism vs. Calvinism in a discussion with David W. I am providing more detail here, since it is off topic for that thread.
The Arminianism / Calvinism debate stems from the tension between our self will and God's authority in salvation.
The hyper-Arminian (extreme case) believes that salvation is a choice entirely up to us. That God offers salvation to all, and some choose God, and some choose themselves. The choice of self leads to an enternity separated from God, which is described as Hell.
The hyper-Calvinist believes God chooses some for salvation and some for damnation. Our own choices play no part. Some could go as far as to say that evangelism is just a symbolic ritual, as those who would be saved, will be.
In reality, everyone falls somewhere in between. I spent a lot of time close to the hyper-Arminian position. It was only recently, upon deeper investigation of scripture, that I have adopted a fairly well-seated Calvinist position. This shows up some in my post, "Why the Gospel does not make sense".