I'm in love with Livebooks right now. I have the student plan ($99 a year) which is great! The non-student price is steep, i think $425 a year. It has an option so send clients to a special part of the site that is password protected, with your choice of password. It also comes with an iPhone version included since it is a flash site. The iPhone version is great because it works with the touch capabilities as you slide through the portfolios.
There are tons of professionals using Livebooks, they even offer professional design services, but that bumps the price up significantly.
There's my two cents 🙂