A number of spark plug mfgrs are recommending to NOT use anti-sieze on their plugs.
There are a few reasons which make sense -
@ plug threads are nickle clad or other aluminum friendly plating
@ too easy to overtorque as torque values are given with dry threads
@ not all anti-seize compounds are conductive
@ potential for fouling the plug by over application
@ potential for contamination of the insuator thereby causing a short from the lead to ground
All that said, I personally would not think of installing a plug in an aluminum head without having a small dab of anti-seize on the threads. Just go easy and remember that your torque values should be reduced by 10-15 percent (this is a number I feel relatively safe with - your mileage may vary)...