I just noticed the ticket I raised with Adobe for adding a null-coalescing operator to ColdFusion has been marked "to fix". Nice one!
I suggested two possible syntaxes: either be like C# and use ??, or like Groovy (and Railo) as a variation of the ?: operator. Personally I prefer the former, as I think the similarity to the ?: operator isn't there, and it's confusing/misleading to have the same syntax used for two different things.
But for the sake of sideways compatibility, erring towards how Railo have done it might make the most sense.
I'm liking all these wee developer-centric features going into ColdFusion 11. I'm more excited about this stuff than I am about social media and mobile stuff.