Any recommendations as to what type of gigibit wifi router I should purchase?
For nearly everyone here, when they say "router" they mean Small Office or Home router/firewall/access point.
I would start by asking "what devices are you going to use?"
If everything in your house is on WiFi, then WiFi is going to be the bottleneck, and you want one of the higher-numbered AC routers -- something with MIMO and multiple streams. Try to get the router near the middle of your devices.
It's better if you can get some or all of your devices on wired connections.
That's if you think you can get close to actually using a full gigabit.
I've actually been measuring my bandwidth (I use a commercial router on my crappy Frontier DSL) and my usage is peaking at around 2 megabits. I don't see bandwidth as an issue with Frontier, I see latency.
I think a 100 megabit router would be just as good, except that you wouldn't be able to brag about speed test results (or watch more than 3 4K UHD video streams).
That said, we all want to optimize things. I'll keep my (commercial grade) router in my office, and add a Ubiquiti UniFi AP-AC-LR in the living room, near the ceiling. I'm also going to run a wire to my Roku to take it off the WiFi, just because I can.