I'm gonna have to agree with the interior. The dark gray is nice. I don't have any experience with the bisque prius interior, but my sister's beige interior in her 08 Civic is FUGLY after being stained from normal wear.
White is bad it shows dirt and grime easily but black shows everything. Dirt, grime, water marks EVERYTHING. You can't wash the car on a sunny day because the car gets too hot and dries with water and soap on it if yur not watching it like a hawk. Even with that your going to have to invest in gallons of quick detailed to get water marks out. And unless your car is garage kept, the dew that forms over night will even leave water marks which means your car is never clean for more then 12 hours. White is a little better but IME it's more of a pain to wash because you will end up snow blind on a bright day...anything in the silver family is best. Silver hides the world. Idk why it works so well but the car will look clean for weeks
Black is the absence of color, so anything that has color that sticks to it shows up like a sore thumb.