Anything over 100 Mb is overkill for streaming. Gig internet service will not improve your streaming quality one bit.
The most important thing is to have good wireless coverage within the home and use ethernet where practical.
Not true. If you have multiple devices streaming at the same time you need more bandwidth, that is a given. The issue comes that comes up is that most homes will have bottlenecks because their firewall and wifi become chokepoints because they do not have the throughput to take advantage of the large pipe they are paying for.
I have wired my house with Cat6 where I can and I have gigabit switches with multiple bonded trunks to handle the bandwidth and vlan traffic. Wireless covers my whole house. I will be upgrading my firewall to enable 500mb throughput for regular traffic. Why? Because this is what I do for a living.