After hearing about the R-value and RNG incidences,
I wondering if the private key of the address can really be derived or the intruder must have got in another way.
I posted on reddit few days ago, http://www.reddit.com/r/Bitcoin/comments/23ybk8/just_came_back_from_hospital_for_appendix_rupture/
but it's such a big amount that I couldn't let go,
TLDR:, the address is from my blockchain.info wallet, I made a big mistake importing it to my main wallet, forgot about it, and one day decided to randomly pick an address to receive 151 BTC, turned out that I picked that address, 2 months later, 150 BTC traveled on its own out of the address, it took me 5 days to realized the loss.
I wasn't sure how I signed up for my blockchain.info wallet. I cannot find prove that I used browser to sign up that day, there is a slight chance that it could be an android device.
Condolences.