A couple of years ago I spent some time playing around the thoughts and ideas of William James as they present themselves in 'The Varieties of Religious Experience,' (As you do). This is a basic summary of his thesis followed by some of the thoughts that came to mind.
Religious experiences contain usually four distinguishable traits, namely, passivity, ineffability, noetic quality, and transience; by these four can we claim an experience to be 'religious.' (N.b. by religious in this sense, James is referring primarily to the mystical spectrum that accompanies religion.) These four basically mean:
Passivity - the individual within the experience has little or no control over the experience
Ineffability - the individual finds the experience near impossible to explain to someone who has not had a similar experience
Noetic Quality - the experience provides some degree of insight into truth, such as interpreting the present, explaining the past, or predicting the future
Transience - the experience was induced by deity/deities above and beyond rational understanding and perceptions
James would not classify himself as a believer in the deity of classical theism (or he is not a Christian for those of us that speeketh English) but I do feel a degree of truth resounding through this...once we distort it and make it our own :P I believe it was Mark Twain who famously said 'First get all the facts then distort them as you please.' With that infallible statement I'll continue.
It just really struck me that theologically, when we 'experience' God it contains an aspect of all of these traits. Lets take a couple of reasonably uncontroversial examples. When we read the Word of God in scripture, there is a degree of transience, the authority of one much bigger than ourselves, and with that an acclamation of authority and the necessity of submission. There is definitely an element of Noetic Quality, interpreting the place of humankind, the universe and its response to God on a large scale, and individual heart-warming situational guidance in obedience and faith; this is not to mention the prophecies such as the return of Christ in glory. There is an element of ineffability, the inability to explain the immensity of grace and the totality of the riches of the gospel as they have impacted our life and how they resonate in beautiful melody when we flick through its pages. Finally there is an element of passivity, a feeling of 'this is something actively leading me into truth and revealing to me the nature of God.'
Or lets take another example of singing praises to our God. There is obviously transience, worshiping Him who is so much bigger than me and so worthy of it. There is definitely a noetic quality in finding ourselves aware through the stirring of our hearts and the words we are singing, of our place before almighty God, and the appropriate response to Him; a recontexualising of our being. There is a passivity, knowing that we are to follow his command in praising Him and connecting with the truths we are claiming through song, submitting to those truths by asserting them (maybe). And there is a degree on ineffability, its difficult to explain the joy of singing praise to God to someone who doesn't see God as a true recipient worthy of praise.
I think the main reason I find James helpful is that it creates an awareness in my life of the multifaceted and spiritual connection I make with my Father God as I live to serve and love Him. It reminds me that each action of my life with I make to be worship (which should be every action), is drenched in a transience, in a revelation of truth and intimacy, in a passivity, or submission and obedience, and in a separateness from the world. Praise God for such a powerful and obvious relational connection in our lives!