The average light switch and corresponding circuit is rated at 15 amps. To see how many CFLs it will handle, first compute the total watts the circuit is capable of by multiplying 15 (amps) times household voltage, 120 volts (assuming you're in the USA). That gives you a maximum load potential of 1800 watts available for that circuit. Then, add the total (actual, not equivalent) wattage of the CFLs you intend to use. Let's assume you're using a CFL with the equivalent output of a 100 watt incandescent bulb. The actual power consumption for a 100 watt equivalent CFL usually runs between 23 and 30 watts. Let's assume 30 watts (worst case scenario). Let's also assume you have 10 sockets instead of 7, for ease of computation. 30 watts times 10 bulbs equals 300 watts. Given these data, you could run 50 more CFLs off that one circuit. Compare that to 18 100 watt incandescents and you have a pretty good idea of the power savings of CFLs. And this doesn't even take into consideration the room heating that takes place with power hungry Edison bulbs.
The only drawback I've found with CFLs is their ballast (the electronics in the base) makes them somewhat frail when compared to incandescent lamps. They don't like confined spaces. The electrolytic capacitors and other electronics can suffer from heat build up. So, use them in an open fixture only.
Me, I have an intimate knowledge of things electronic and electrical.