i'm not in the industry but from what i know you should target your portfolio to the area you want to go in, the same way you tailor your cv to a job, you tailor your portfolio to it too

if you're going for a modelling job you show your work with wireframes as well so the posible employees can see your topology

lighting you show off lighting more than anything else

same with textures and animation

i think you need a demo reel as well, usually put onto VHS (since studios still use such things apparently, even though digital is becoming commercial VHS is still used)
don't bother putting sound into a demo reel cuz no one plays them with sound

of course, these are claims i recall from someone at a siggraph conference either this or last year.

have you ever been in a job interview before? (any job interview, not just one for this industry)