technically speaking, if you add the amps for the moniter and the amps for the cpu for each person.. as long as that amount it under the amps listed on the circuit.. you would be fine...
now for the real answer: it's kinda like overclocking.. max it out and then back off a bit... when you plug in that last moniter and everyone's screens flicker, it's probably a good idea not to hook the moniter (or computer) up to that circuit
it all depends on the circuit though... at hotel conference rooms we can usually do about a dozen, maybe 15 comps before tripping the circuit (which tends to be the whole conference room, and thus large capacity)
whereas, at UCF, we took up the large conference room, about 50 people or so and never had a single problem