What is saving faith? A common soteriological view among Evangelical Christians (such as myself) is that we are saved by grace, through faith alone (Ephesians 2:8-9).  However, this belief is usually accompanied by a belief that the inevitable effect of salvation is a life that bears fruit, and gradually conforms to Christ (sanctification).

1 John 3:9 (NIV)
9 No one who is born of God will continue to sin, because God’s seed remains in them; they cannot go on sinning, because they have been born of God.
Matthew 7:18 (NIV)
18 A good tree cannot bear bad fruit, and a bad tree cannot bear good fruit.
James 2:17-19 (NIV)
17 In the same way, faith by itself, if it is not accompanied by action, is dead.
18 But someone will say, “You have faith; I have deeds.”
   Show me your faith without deeds, and I will show you my faith by my deeds. 19 You believe that there is one God. Good! Even the demons believe that—and shudder.
James 2:24 (NIV)
24 You see that a person is considered righteous by what they do and not by faith alone.

It seems clear, especially from James, that genuine saving faith is accompanied by works.  Of course, since we are not saved by works, we conclude that these works are the fruit of our salvation, and not the cause of it.  In other words, we are first saved by grace through our genuine saving faith, and works result.
So it seems that it is possible to have a faith that is non-genuine, or non-saving, and thus does not lead to the bearing of fruit.  My question centers around what the difference between these two types of faith is.
I'm interested in non-Calvinist viewpoints, because I believe that I understand the Calvinist one.
I think a Calvinist's answer to this problem would be that it is God who initiates the salvation process in the elect, and saving faith is the result.  Non-Calvinists would hold that God initiates the salvation process for everyone and draws all men to him, but we must choose Him.  So it is in the non-Calvinist viewpoint that the question arises: If there is such thing as a non-saving faith, or non-genuine &quot;choosing&quot;, what characterizes saving faith?
I think the short answer that's easiest to give to another person is that if you really believe the message the Christ brought to mankind, it will change you, and that change will show in your actions. Not that you must do change your behavior to attain salvation, but that coming to believe what saves us by faith cannot but change your behavior.

By contrast, it is very easy to say that one believes something, whether or not it is true. The profession of belief is important, but when one declares a belief and that belief is not reflected in their behavior, it is suspect. 

Perhaps I'm arguing semantics here, but I think it's meaningful that James says "You say you believe there is one God," as opposed to, say, "You say you believe Jesus Christ is the Messiah who died for your sins." I think James is pointing out that simply believing in the existence of God is a baseline, not the endpoint of faith. If that's the case, then such a belief isn't nearly as formative of behavior as belief that one is a sinner who can be forgiven. James seems to be saying faith should manifest action because real faith is in something transforming.