i store my consoles in those plastic sweater boxes with cables and such. When i watch the Angry Video Game Nerd hooking up an Atari5200 with all those systems hooked-up at once, i scream "FIRE HAZZARD!" it freaks me out.
i hook mine up, play, when i want to switch, it goes back in it's box, onto the plastic etagere and then the other one gets hooked up. I even trained my son, who would want to play one system, then a different one, then...smack! one system at a time!
so, BOTH
(but Sega Genesis is my fave)
ummm ... how is it any more of a fire hazard than having a computer + monitor + printer + speakers all plugged in at once? It's not like anyone's saying to daisy chain power strips ... which is the only time it is ever really a fire hazard. It's actually better than plugging them strait into the wall so ... (I may not personally know too much on the mater, but my dad's never complained about it and he's a Fire Lieutenant over here).
On Topic: Choosing both is probably smart 
you can't really go wrong with either system, it just comes down to Nintendo games vs Sega games.
well, it was always a HUGE deal in college.
and, it's so messy looking, i can't stand all the clutter.
but, it's just my opinion. And your fire-marshall dad isn't ours. Even at school, they are extremely picky about what we can have plugged up.
as for office and TV, i actually had an electrician install heavier Gauge (? i think it was what he called it) so that i could draw more power off of those outlets. The wires going thru the walls to the box are specifically designed for it. On the TV i do have this cool power switch box that allows me to completely cut-off flow to items i don't want to have residual drain from (like a LCD of a VCR...i HATE the green lights that blair into the night darkness).
Plus, hooking up a Laserdisc player or something like that, it's much more HEAVY and difficult, so they stay put, and have their power off.
