Should Rice be soaked before cooking?
Rinsing the rice is always suggested, it removes the leftover husk, powder from the rice being handled and/or processed, insect fragments (you'd be amazed!) and more.

Soaking the rice is part of the cooking process. Wild and brown rice benefit from this because they'll more evenly cook 'to the tooth (al dente)' with less liquid and time; this is how you get a nice and fluffy pilaf. If you don't soak the rice before cooking, it will require more liquid and time, and be more likely to come out clumpy and overcooked.

Most good markets have dozens of kinds of rice and each one does best with a different kind of process and finesse. And we haven't even talked about Sushi rice or Arborio (literally: "absorbent") rice yet.  

Soaking long-grain or basmati rice has benefits too, depending on how you season it. If you like to cook your rice with achiote powder and safflower strands, soaking in some warm water for an hour is really helpful. 

Some South East Asian recipes call for the liquid where rice was soaked for a few hours as a thickener or ad-hoc liaison. Tinola (a brothy chicken dish) is one, sinigang na baboy (sour pork soup) another. A fan of either dish can tell when the broth is missing that starchy quality only rice can bring. Rice flour, or cornstarch, even in small amounts, would be too much.

So. tl;dr;:


Always wash whole rice for hygienic purposes.
Consider soaking the rice as part of the technique of cooking it, but make sure it's a conscious decision, e.g. "I think soaking it will yield [result]"
Pre-packaged parboiled rice usually doesn't need to be washed or soaked, follow the packager's directions and your own instincts / experience.