depending on where you live and availability, comcast is now offering streampix (a direct competitor to netflix, with similar content) for $4.99 in addition to one of their xfinity TV services (i'm not a fan of my antenna's ability to pull in locals, so maybe see if you can add it to the basic package if it's in your area). also, there's an xfinity app for the 360 if you have xfinity internet service, Comcast says your use of it will not count against your monthly bandwidth cap.
i also use PlayOn, which picks up amazon prime (best $79 i ever spent, because i order a lot online and free 2-day shipping is awesome, they throw in the video streaming for free), some of the networks, and several other providers, and it works perfectly well for me on my 360, my PS3, and many other devices. they have a 'lifetime' offer going on right now for $49.99
my sister cut the cord last year and never looked back. PlayOn, hulu, netflix, and an antenna, and her family is perfectly happy.