Spark plugs

I have a 1980 kz1000a.  Should I use copper, platinum or iridium spark Plugs?

Use non resistor NGK or ND plugs.  I think these may be denoted "copper" but that detail doesn't matter.

NGK B8ES
ND X24ES or X24ES-U

Don't use plugs with an "R" in the designation, because that indicates "resistor."

As above. 
It doesn't need anything fancy.
NGK B8ES or the equivalent for a stock machine.

I thought we're supposed to have resistance somewhere be it a plug, a cap, but not both?

Gdailey2112 wrote:

I thought we're supposed to have resistance somewhere be it a plug, a cap, but not both?

At the most you have only one source of resistance be it the plug , cap or lead.
At the least you don't need any form of resistance if you don't have any electrical components that may be affected and the neighbours don't figure out why the tv keeps going fuzzy when you ride by.