I'm with bangbang and others. I salt and pepper before grilling and as GB says, I sometimes have to salt and pepper again.
I believe you need to season before you cook. The flavor is different. Not as sharp when compared to salting after.
If a steak is particularly nice, I prepare it kosher style. In other words, I smother both sides with kosher salt and let it drain for an hour at room temperature, then I wash the excess salt off and grill. Amazingly, it's not too salty unless you try this with a thin piece of meat. I only do this with 2" or better steaks.