I think Windows 8 will do well and that will be a surprise. I think particularly with the less experienced PC user crowd. WinTel aint' done yet and there is still a lot of room for them to get together on phones.
The real pull is a consistent OS across all devices. Soon Intel will allow a smartphone to do what desktops only could do in the past. At that point the same OS and the same capabilities on each and every device someone owns is pretty convenient.