Those who hold to "man's free will" would agree that man has the capacity to choose between good and evil.  This would indicate that there is some internal mechanism that can be superimposed upon the will so that it can live a perfect life.
I would challenge the "free will" holders to examine the Scriptures and state of living and find in what condition did man not fail.
In the perfection of the garden - man failed.
In the time before the flood - man failed.
Between Noah and Abraham - man failed.
From Abraham through the cross - man failed.
Throughout the church age - man failed.
In the tribulation - man will fail.
In the millennial reign - man will fail.
When does man NOT fail?
When man is given a New Nature (which includes a new will).  As Paul states there is a war that continues between the new and old natures.  Man may be subject to either will, but there is no FREE will, no freedom of choice.  
The old will leads to destruction, the new will leads to life.
There is no in between freedom of will.  The will is not free, nor is the subjection.
Some would say providing alternatives would indicate the capacity to choose.  But that is assuming that all alternatives are attainable.  All that a person in the old nature can do is respond to the will of the old nature.  The fallen man has no ability to attain, grasp, receive, ... anything of the nature and spirit of God.  
If the will is fallen, the consequence of all that will's ways are a life of destruction as the whole of human history has validated.
If a new nature resides within the believer, there is still no "free will" but a new will that wars against the old nature.  By the believer being given the new nature, there is still no "freedom of choice."   Either, the persons' old will rules and the body will be destroyed - yet the person saved, or the new will rules and the person enjoys the things of the Spirit of God.
There is no "freedom of choice" for both wills have consequences.
This is difficult for those of the modern century to understand.  We have all been raised with the thinking that a man has the capacity to choose what is just or unjust.  But, the natural person's will cannot accept anything of God.  In like manner, the new nature person's will cannot accept anything of the world.
Example, the room is dark.  A Light is turned on.  The room does not loose all the darkness, but the darkness lurks waiting for the light to be turned out.
Who is in charge of turning on and off the light?  
Some on this thread would say, the natural man can.  No, because the room cannot and does not illuminate itself.  God turns on the light on or off.