Congratulations.

Lesson one. There is no difference between your finances and your in-laws finances. It can go either way.

I think it depends on who is paying for the reception.

For my wedding (almost 9 years ago) I paid for the wedding and handed the Hongbao to the mother-in-law, she told me we had made a 2000RMB profit and offered me the money, I told her to keep it.

Best investment I ever made.

I agree with Scandinavian. It is possible that the parents keep the money and give you something in the future if you need it, or that you keep the money but you will have to share it with your parents-in-law at some point if they want to start a new business or lend it to someone else.

We kept the money. I heard from my wife her parents had some kind of separate party in her hometown where they got their due. 

I agree with Hugh. By tradition, it should go to the newlyweds, but out of practicality it goes to whoever paid for the wedding. Whatever is left over the newlyweds get to keep. Now, if you do as Hugh did, and let the inlaws keep the "profit", that may be a very good way of starting off on the right foot with them UNLESS they sound like the "inlaws from hell".

Usually goes to the newly weds, depending on who paid for the party. Your in-laws will probably know how much each relative will give so they usually arrange the party and you give them the money for it.

This is the usual case but it would be best to ask your future wife about her family traditions.

At my wedding the money was given to us, but my wife gave the money to her parents to pay for the party. The didn't accept the money though.