Transverse or longitudinal waves, purely as a matter of aesthetic preference? Transverse all the way, of course.
Not that there’s a huge difference mathematically speaking. It’s more of a species-type categorization than a rigorously formal one. Transverse waves oscillate perpendicular to their direction of motion, longitudinal waves oscillate parallel. This stuff does however give me a chance to spread the light (ahem) on a common misconception my 208 students often seem to have. This is the type of picture usually presented in physics textbooks of a transverse wave (a light wave in this case), with its twin perpendicular electric and magnetic oscillations:
So if you picture a water wave propagating outward you notice that the wave has a certain size. The amplitude is just the height of each wave. Light ain’t like that. There’s no physical “size” of the up and down oscillations in terms of spatial extent, certainly not in this purely classical plane-wave sense. When students perfectly reasonably look at pictures of waves, they built up a misconception in their heads that light in some sense takes up space and needs room to wiggle. But what’s oscillating is not a physical substance moving up and down. What’s oscillating is the strength of the electric and magnetic fields. The up-and-down displacement of the printed wave in the diagram represents the strength of the field at that point. Nothing’s actually moving up and down, and thus the wave isn’t taking up space – not by virtue of its amplitude, anyway. A wave with higher amplitude will not get “stuck” in its passage through a small opening any more than a wave with small amplitude will.
Thus light as a wave is a little more abstract than waves of spatial displacement. A subtle point, but an important one.