I don't have a 3D tv so this would not effect me. I don't think 3D will be a big concern around launch seeing as none of the titles announce are known to support 3D. So 3D at launch will likely not happen, but post launch and into 2013 and 2014 might be the point where 3D will be supported.

I played Batman Arkham City in 3D on my PS3 and have been playing Assassins Creed: Revelations in 3D so I suspect that Assassins Creed 3 would support 3D at least on the PS3.

I remeber reading an IGN article that was an interview with somebody with Nintendo stating that Nintendo says that they intend to make the Wii U 3D ready because they fear that 3D conole gaming will be the next thing. However they said it would be part of an update. I looks like Nintendo learned a lesson with the Wii and DS and making the 3DS and WII U have more updates that great IMO. Anyways I cant find the EXACT article but I think it was somewhere during 2010-2011 hope that helps!