As a Linux user I would be extremely pleased if there was a Linux version released (and by extension SteamOS since it's just another Linux distro) so I don't have to boot into Windows anymore since Wine doesn't run ARR well at all.

Will it happen? While I will keep hoping, I seriously doubt it. Steam Machines, as Zaineal said, will have an extremely small userbase that won't justify the expense of porting the game over to Linux (and OpenGL since ARR is a DirectX game).

There are some developers dabbling in Linux though, so it isn't completely out of the question. Just highly unlikely.

I hope Steam Machines do well. And I know I'll be taking a look at SteamOS when it comes out in a couple of days. If they do take off, and ARR gets a Linux release, it wouldn't be for quite a long time.