Bitcoin 2.0 can be used to refer to:

-Some time from now after there have been major updates & changes to the protocol which in combination with more secure, user friendly services and platform built on top of bitcoin provide a radically more useful tools that could be used for things developers have yet to have even considered that go beyond payment processing

-A new alt-coin or virtual property market that is a dramatic and obvious improvement on bitcoin

At least that's how I've seen it used on Let's Talk Bitcoin podcasts