In my house, I have over 50 ethernet devices in various places. I have a 24 port and 8 port gigabit switch in my office. Those are both individually connected to my Linksys Router.
I have a 16 port gigabit switch in the living room which feeds three satellite receivers, PS/3, Apple TV, WD-Live, Xbox 360, two computers, Two Slingboxes This is connected to one port on the 24 port switch
I have an 8 port 100 mb switch in my office which is my telephony network. It has three SIP boxes, and two SIP phones, along with the Asterisk linux box connected to it. That is connected to the linksys router also with priority on that port.
I have an 8 port gigabit switch in my basement theater which feeds: PS/3, Satellite Receiver, WD-Live, Computer, HD-DVD Player Also connected to the 24 port switch
My older daughter has an 8 port gig switch in her room which feeds her various computers (she has 6 of them). This is also connected to the 24 port switch
My younger daughter has a 5 port gig switch which feeds her desktop, and the WD-live in my bedroom. This is also connected to the 24 port switch
In case anyone asks, the brands of the different switches are pretty much all different. the Ethernet Spec is so well standardized that it is no problem with different brands.
Also in case anyone asks, I do have wireless also, but nothing beats a reliable wired connection for video streaming. I stream content from my file server which has over 34 TB of storage right now. Because of the fact that we have at least 8 wireless only devices (iPads, Phones, laptops that get used only in wireless situations, audio media players), I prefer to have anything streaming video as a wired connection.