How to Share music between two libraries / Apple ID's?

So my boyfriend and I have moved in together and will soon be utilizing the same computer. I have an Apple ID and music library, he has an Apple ID and music library. I would like to create a separate login to the computer so we can still keep our separate ID's / libraries for syncing purposes (making sure we each have our own Calendars, Contacts, Photos, etc...) but would like to Share music with one another and be able to add it to our iPhone's without having to buy or download it twice.

A couple of things below

• What's the easiest way to transfer all of my current information to his computer? External hard drive?
• What's the easiest way to share music and / or apps while keeping individual Apple ID's?
• Will the Home Sharing option work here?
• OR, will we have to create a new Apple ID, transfer our information to that new ID, and create two separate libraries off of that?

Any and all advice is appreciated. Trying to make this as easy and painless as possible 🙂