Ok, I have reached the point where studying and writing the 70-640 exam, Configuring Windows Server 2008 Active Directory, has left me financially and mentally drained.
I've attempted the exam five times and failed five times. Really thought I would pass it on my second attempt, but got an even lower score than my first attempt.
Passed the selective exam, 70-620, Configuring Windows Vista Client, three years ago, before I was forced to stop training, because of a new job, which kept me busy 24/7. When I started training for 2008 again, the exams have changed and I needed to get the new 2008 R2 training material. I choosed to soldier on with the original 2008 books, which in hindsight, was a big mistake.
Still wondering if Microsoft did not fail me because I studied the Vista Client and not Windows 7 Client, but that would be bad sportmanship from my side.

My financial resources have now dried up, as well as my willpower & time to complete the MCITP 2008 certification.
I've decided to give it a rest for a while, and wait for the Windows Server 2012 R2 training material to become available, before getting qualified as a 2012 R2 engineer. Yes, I'm not kidding, Server 2012 already has a R2 version.
The irony is that I have been appointed now as a senior Windows Server 2008 network administrator, so will still be working with Windows Server 2008 R2 for the foreseeable future.

I wish you all the best of luck and success with your further studies, I will most probably surface again in the Server 2012 R2 threads.
Have fun!!