I get it really comes down to how many power outlets you have in your room. Like I got my 2 rigs + periphals (specs below) plus 1 8xport switch, 1 4xPort Router 1 Cable Modem, 1small stereo, heater or fan (depending on time of the year), MP3 Player Charger and 2x Mobile Phone Chargers coming from 1 wall socket. In order to do this, I have 3 power board piggy backing each other.
This this a fire hazard.... yes!
Luckly, I have 1 fuse in my fuse box dedicated just for my computer room.
When I was living with my parents place, all it took me to blow a fuse with my computer room was to have the heater running, the computer on, the TV on, the stereo (with was connected to the computer) on, and then have me send a print job to the laser printer.
So I had to remember to turn off my heater before printing.
Yes, it can a fire hazard.
It really comes down to how much current are you trying to take from location in your house.