I had been running 100Mbit for a while, but recently upgraded to gigabit since they’re now extremely affordable.
My house is pre-wired with cat 6 cables, so I have all of this in my bedroom closet (where all of the wiring is). I just patch into the rooms, which already have network jacks in them.
The living room has an Xbox 360, Wii, classic Xbox, and HTPC, so I use a 5-port gigabit switch to break out that jack.
I also have another 5-port Netgear gigabit switch in my office to break out my office jack.