The November 16, 2008 issue of the New York Times Magazine has an interesting piece titled "The Brand-ness of Strangers."
It reports some research on the effects brands have on us. Among other findings, people who saw photos that included a bottle of Dasani were more likely to choose that brand when given a choice of four brands, even though they didn't consciously notice the bottle when looking at the photograph (they were asked to focus on the expressions of the people, not other things in the photo).
The article concludes with a discussion of Ralph Lauren's many lines. The Polo logo is widespread, but the logo "is completely absent from Lauren's high-end subbrands, presumably on the theory that the discerning self-identities of such status-conscious consumers clash with flashing an emblem worn by the masses."