I made an attempt to get a huge feedback from the community's active members on this question, but my Poll was flawed as it was "leading" so I will try again.
previous poll: http://forum.ethereum.org/discussion/comment/5740/#Comment_5740
PoS vs PoW for Ethereum 21 votes
PoS, proof of stake (100%)
PoW, proof of work (100%)
PoW/PoS combination (please explain your answer)