Ditto on the good question, I don’t think a lot of people really know what those in hiring positions want to see…
I would say that a little bit of everything is always a good way to go. Don’t just show Alias stuff, don’t just show sketches, don’t just…well, you get it…
Mainly, don’t be one-dimensional.
I think portfolio websites, by design, have to be refined over time, with feedback from those people who view it. They are your best source of criticism and critique.
I threw a portfolio site together kind of quickly and there are some things I’d like to change, but for me, the most important thing was getting my work online, and easily accessible. I think it’s a lot more effective than worrying about the size of your email attachments.
I didn’t put any type of descriptions on any of the work, thinking that might lead to more questions from the sites visitors. It worked, but a lot of the feedback I’ve gotten has included requests for short descriptions on a per project basis…
I think another things people get carried away with is a kick-ass site, but they don’t do a good job of showing off the work they’ve done. Don’t let the design of your site take away from the work contained within it…
Good luck.