It looks to me like Agave desmettiana varieagata. It is supposed to be cold sensitive with damage occuring at less than 25 deg F. If you can stand to let it happen, it will be interesting to see what happens in your cold winter. There's not a lot of study on cold tolerance of these plants.

Buck

It sure is a nice Agave MBT. Never know, when you ask for a cutting, they might offer you the whole plant! :)

CP

Thanks for the ID. Although I think we may have an answer to whether it will live her for a winter already. I walked past the house to check on the plant and all the leaves were wilted and dead looking, that pic was taken about a week ago.