I've studied hundreds of meditation techniques, both traditional and the "electronically assisted" types, and while the latter can be interesting, I keep going back to the simpler, more traditional forms, such as zazen[1] and vipassana[2].
Listening to external aural stimuli can help alter your brainwave frequency, but at some point you have to go beyond the dependence on them and develop your own innate skills so that you can get into state anytime anywhere under any conditions. Tapes and CDs cannot meditate for you. You have to do the real work.
The qigong state is the aim of this meditation and it is the state of emptiness. It is the no-mind state of relaxed concentration with no thoughts. It is a quantum step closer to pure consciousness.
The difficulty is that the undisciplined mind cannot keep out the stray random thoughts for very long. When you develop your power to concentrate and can hold the empty mind for longer periods, then you become fully present with the exercises and the meditation. Acquiring this skill pays off immensely. You will derive much more benefit from the exercises than if you constantly allow your mind to wander.
Thoughts intrude upon the mind because of the attachments of the ego. Control the ego by releasing attachments. The no-mind state allows you to be more intuitively receptive, go deeper within your core, merge with the universe, and eventually go beyond duality into Oneness with all that is. This is enlightenment, the goal of spiritual seekers.
shr33m

[1] http://www.mro.org/zmm/zazen.shtml
[2] http://www.dhamma.org/vipassan.htm