Umm... basically, the only spark plugs you should buy for your car are NGKs or Densos. In fact, don't buy into any of the hype with an aftermarket ignition. If Erik's Racing 9 second all motor civic (with a B18C1) uses stock ignition, then I'm sure it's good enough for my use.

On my GS-R, I use OE copper NGK plugs from an LS, regapped to GS-R spec. Since copper's one of the best conductors, it produces one of the best sparks. The problem with copper is that the plugs last 10-15K miles AT MOST, so be prepared to replace them at least once a year... but you should be checking your spark plugs every couple months to monitor your engine's condition anyways

I remember hearing that some Miata owners were claiming a whp boost of 3hp by using copper over platinum plugs. Who knows? I've never dyno'd with just a plug change, but you will certainly feel an improvement if you're in need of new plugs.