Rav- as the others have pointed out, lures in the 6-8" range are effective for a host of offshore species. you can maximize the effectiveness of your spread by utilizing a number of lures in a daisy chain. so if you find some lures that you're sold on, don't just pick up one or two.
color is also an important consideration. I suggest that you pick up several colors (pink/blue, green/yellow, purple/black comprise most of the colors in my spread)