Even if you have several devices on the network, they are sharing that bandwidth, so would there be any noticeable difference between a gigabit Ethernet port on or a 100 Mbps Ethernet port in such a situation?
If you are talking about doing absolutely nothing but internet from one device, then you will see little difference between fast (100Mbps) and gigabit ethernet (1000Mbps).
But I hope you are backing up.. and if you do that from a laptop that means using the local network rather than hard disk plugged in when you remember. Time Machine is highly inefficient and slow networks make it hugely more difficult to get backups done within the 1hr incremental time.. you want those backups to go through fast.. as any use of wifi on the network to do backups is going to drastically reduce your internet speed. Once you add multiple computers and a few devices.. fast ethernet can really start to lag.
Cost wise.. gigabit is pretty much the standard. If you ensure all your local network is gigabit.. that will allow for better response for the slow items like wifi and yes.. you do notice it once you build out the network a bit. With just two people in the house now my main router can show 20 devices online.. and that is without much in the way of home automation.
(thankfully rarely) 10 MbE ThinWire
MrHoffman .. has been in the game a long time to see Thickwire and Twisted Pair transceivers. I have a few of those transceivers lying around. I used to rewire them for RS232 serial to cat5 for all sorts of things.
I wired my house 10BaseT.. at a time when only business used networking and a fast cable connection >10Mbps before they slapped limits on it.. my kids hosted networking gaming parties in basement area of the house. That made us the most popular family in the area. We had to run extension electric cables because they would throw the breakers with all the CRT monitors and huge computers of the time.
But twisted pair soon took over.. and working on a 10Mbps network was hopeless once we got even 100Mbps. I have only just finished totally rewiring with Cat6 on really long runs.. trying to use Powerline adapters or wifi bridges. They worked but in the end just cause trouble.
For my needs gigabit is fine.. but I see people now using 10GbE in their homes.. and it is good to plan when wiring to plan for upgrades once 10G switches etc become cheaper.