Congrats on your purchase! You do not need Xbox Live Gold to play games, unless you're kids are going to be playing online with friends/family or if you plan on using any of the streaming services. If yes, then I would suggest you purchase the family subscription which is $99/year as it has parental controls and those do come in handy. If not, you can get a free account. Yes you would need to pay for Hulu and Netflix, which both cost about $8/month on top of a family Xbox account. You can go to both companies websites and decide if these are worth it to you. Crackle is free and has movies and if you belong to Amazon Prime you can watch their library of free stuff as well. I have high-speed internet so my streaming (when I use it, which is hardly ever) is pretty good via wi-fi. Only other things I can think of is maybe an HDMI cable to hook it up and an extra controller.
My flabber has been gasted and my gob has been smacked. Anything else?