However, the "we're talking [something]" construction is a common but slangy way of emphasizing that the thing you're "talking" is big, important, notorious, or the like. It is very informal and is generally not used in serious writing or speech. It has also become rather a cliche.
Do you agree with the following explanation of the difference betwee "let's talk about money" and "let's talk money"?
If you say "let's talk about money", you might want to discuss the history of bank note printing, or the dealings of the European banks: "money" is in this case quite general.
"Let's talk money" means you want to talk about money that will change hands between you and the person you are talking to. You are talking about some kind of deal, and you propose to discuss the financial part of the transaction now.