I'm planning to
Add some hd security cams in the future. They require Poe switches. Do all switches do PoE or are there specific switches for that.
It has to be a PoE switch and there are many options now days.
If you only need an 8 port switch today, double it. Get a 16 port switch.
Having that said. You don't have to get a 16 port switch. You can use a 4 port switch as your main PoE switch, and add more PoE switches in various rooms in your house with out running additional cables.
You could get wifi security cameras and place them anywhere near an AC outlet, this way you wouldn't have to run additional LAN cables and you don't have to use a multiple PoE switches.
There are many options to accomplish your main goal. You know your house better than I do, so plan accordingly.
If its fairly easy to run additional CAT 6 cables to all 3 floors, then do so. Run 3-4 more per floor, if its easy. This will eliminate having multiple switches.
I also don't know where you will mount security cameras. Will you place them indoor or outdoor, or combination of both??
Are you going to add DVR for cameras? Are yo going to use a TV to view video from cameras? Or are the cameras will stream to a PC, a PC that will record video from all cameras??
How about a NAS with dual Gig ports, that will store video from security cameras and 2nd NAS that will store your work data?
Are you planing to add a standalone Firewall to protect all the data; "video and work related documents"?