What happens when i transfer my SIM card on an iPhone?

So, say I move my SIM card from my iPhone 5 into an iPhone 6.
-Will it transfer all my music, photos, etc?
-If I have a specific data plan (5gb per month, for example), will that data plan also transfer over?
-Does anything stay on the 5?

The SIM card represents your wireless account and phone number. Moving the SIM tells the new phone to adopt the phone number, account, voicemails, and data plan. You will still need to sign into your Apple ID to synchronize with iCloud. Before making the move, back up your old phone to iCloud or your computer's iTunes as a safety measure. Don't forget to sign out of the old phone and erase it before you give it away.

No…

The SIM card is not a memory card (this is having to be mentioned much more recently for some reason…)

The data plan (sort of) would go over since it is assigned to the SIM, more specifically the number the SIM has assigned to it. Though it would require some configuration on the newer iPhone.

So as far as anything staying on the SIM, pretty much everything would, since again, the SIM isn't a memory card.