What are the most important topics to discuss before moving in with a partner?

Finances, and sharing or responsibilities

How the bills will be split, if you're pets/kids, are compatible..common sense stuff, really

Finances, Food choices, cleanliness

You know...the important stuff. Like agreeing on whether the toilet paper roll goes in the over or under position.

my wife is a Judge Judy Junkie, and one thing i've learned is, get EVERYTHING in writing!!!

Finances, chores, and houseguests.

Finances and splitting of household responsibilities.

If she's going to serve me food and beer when the footballs on.