I've worked out of a series of no's. No to exquisite light, no to apparent compositions, no to the seduction of poses or narrative. And all these no's force me to the "yes." I have a white background. I have the person I'm interested in and the thing that happens between us.
Richard Avedon, 1994
He's one of my favorite portrait photographers (and now The New Yorker's first-ever Staff Photographer), along with his opposite, Arnold Newman. Avedon always works with a white background so as to draw our (and apparently his) attention to the inner nature of his subjects. Newman, in contrast, is an environmental portraitmaker whose theory is that a person's inner nature is best communicated when shown in the context of their own little corner of the universe, often lit and composed carefully and expressionistically.
Check them out. Avedon's website is here (and isn't the young Richard, old Richard thing cool?). Arnold Newman doesn't have his own site, but here's a nice collection of some of his more famous portraits.