Is self-esteem sexy?

In men, absolutely. High self-esteem was the most attractive.

In women, moderate self-esteem was more attractive than high self-esteem:

The provision of information appears to be an important property of self-esteem as evidenced by previous research concerning the status-tracking and status-signaling models of self-esteem. The present studies examine whether there is an implicit theory of self-esteem that leads individuals to assume targets with higher levels of self-esteem possess more desirable characteristics than those with lower levels of self-esteem. Across 6 studies, targets with ostensibly higher levels of self-esteem were generally rated as more attractive and as more desirable relationship partners than those with lower levels of self- esteem. It is important to note, however, that this general trend did not consistently emerge for female targets. Rather, female targets with high self-esteem were often evaluated less positively than those with more moderate levels of self-esteem. The present findings are discussed in the context of an extended informational model of self-esteem consisting of both the status-tracking and status-signaling properties of self-esteem.

Source: “An Implicit Theory of Self-Esteem: The Consequences of Perceived Self-Esteem for Romantic Desirability” from Evolutionary Psychology, 2011. 9(2): 147-180