Most slider-style cases split into two pieces; Incipio's new Triad for iPhone 4 ($30) breaks into three. The hard plastic case has a bottom that juts up, and the top is split into halves. We had a pretty hard time separating them at first, but we'll see if that gets any better over time. There's no button coverage, but the case does have openings for the headphone port, microphone, Sleep/Wake button, volume rocker and side switch, and one wide…
