Eco Friendly Metal Roof or Shingles?

I am in the process of deciding what I should have on my roof before winter. The eco friendly metal roof seems to be my best bet now because they last longer and of course green.
I have been putting off the project for awhile now and the last heavy snow woke me up now I am making plans but I want to avoid a bank loan since house have lost so much value that it is not worth going in debt for it no right now anyway.

No one in my neighbor has a metal roof yet so my house will be the first unless someone else decides very soon. Going cheap is not an option because I do not want to mess with it for at least 50 years-depends on good health care.

No one is yet to come with a plan where one can put renovations as part of a Christmas wish but anyway right now I am looking for immediate solutions.
Choosing an eco friendly roofing material will contribute to energy efficiency especially now that I will keep the original roof by just adding the eco friendly metal roof over the old one.

There several choices out there, metal, rubber, slate or clay but I am yet to select the clear winner although I leaning towards metal right now but I might change my mind that is if you can convince me otherwise.

Therefore, while I sit and ponder let me know what you think I should use. Maybe you already have an eco friendly roof or planning to install one let me know. Remember I am looking for a roof that canwithstand the elements, durable, fire resistant, can be recycled and has to be 100% eco friendly roof.