C# is a great language and Ximian has been doing brilliant work on Mono but I'm actually starting to wonder about the long-term prospects of Microsoft. Without a significant corporate sponsor I'm just not sure it has the momentum to endure.
EDIT : couldn't find 2012 but heres 2011 http://punchcut.com/sites/punchcut.com/files/win8_1-8_eb-msf... business + server looks around 60% which I guess is where my figure comes from