Best to use what is suggested in your owner's manual.
Different configurations of plugs have different resistance.
Your car is set up for the resistance of the plugs you car/sytem was designed for. The whole electronic ignition is dependant on certain factors.
I'm aware of the temptation to put in longer service plugs but you are asking for trouble if you do. Better chance of them seizing into the head even for that long a service interval. Not recommended.
I've always been a fan of platinum plugs, I've had good results from them in many cars and bikes. Iridium plugs seem to be the thing nowadays, those are the ones that Suzuki specify as standard on most models with copper as an option. The plug type won't affect the ignition system as long as you have the correct coil it will be fine.
As was said before Iridium plugs are standard but I was told that unless you are running a turbo you really don't need them, so I have run Platinum plugs in both my 1999 1.6 and 2002 1.8 Esteems and had no problems with them in either car.
I think the real advantage of the Irridium/Platinum plugs is longer life, it makes a major difference if you have a late model V6 vehicle, where the plugs are sometimes buried under the intake - more so on the transverse engine ones, where the rear bank can be almost impossible to reach - some of those have different plugs specified for each bank of cylinders - one bank running platinum on the center electrode, and the other on the ground.