dchanth,
Nope, going from 3rd to 5th causes no problems. If you have a tach, you'll see what it does to the rpms. My only caveat would be that you don't shift to 5th until you know you won't lug the engine.
Keep in mind that gears on a car, like on a bicycle are meant to do one thing; keep the engine running at about the same rate. This is how you get better gas mileage as well.
Bogatyr