Well it all depends man. I would recommend that you pick up a nice quality surge protector / multi-tap. All that **** adds up and it will take it's toll if you don't respect it.
US jacks got 15Amps if you didn't pup a breaker yet you good but your best bet is to go to HomeDepot or walmart and pick-up surge protector like this one for example
we had a old air conditioner once that would trip the breaker about twice a day, then you would have to go down to the basement and flip the breaker back on, we plugged it into the surge protector and then it would trip it instead of the breaker saving us froom having to go to the basement to flip the breaker.
point is they help add protection if the breaker would ever fail.
please allow me to sneak a question in this tread, the only outlet i have in the attic is the one from a/c unit, if i plug a surge protector /code http://www.powersentry.com/products/100373.php /code in the outlet that the a/c is on, will it be too much power for the outlet to handle if a/c, 400watt hps/mh conversion and two 8'' 500cfm 120vac 60hz .75amp duct fan running at the same time? the a/c is not gonna be plugged into the surge protector. please help me out thanks!