I've seen entire apartments supplied with one 15 amp circuit. Now that may not be desirable, but I have no problem running 15 amp circuits for living rooms and lighting.
Right now I have a computer, two sound mixers, DSL modem, printer, monitor, speakers, musical keyboard, bass amplifier, DVD player, VCR, cable box, stereo, television, XBox, lamp, and fan on a single 15 amp circuit. I've had them all on at the same time allowing for many people to entertain themselves in various ways and have never had a problem.