[No] single figure stands out as the current leader of the Republican Party; in fact when asked who they see as the leader of the party these days more volunteer that nobody is (22%) than the most mentioned name, Speaker of the House John Boehner (10%). This is typical for parties out of power. In 2006, for instance, Democratic voters were unable to point to a single leader for their party.
At the same time, however, several prominent Republicans are quite popular with Republican and Republican-leaning voters. Of these, Rep. Paul Ryan stands out as having the most positive image among GOP voters (65% favorable). Not only is Ryan highly visible after his vice-presidential run, but the vast majority of those who know him view him favorably.
Sen. Rand Paul also has a very positive image (55% favorable), as does Sen. Marco Rubio (50%). Sen. Ted Cruz is not as well known as other GOP figures, but his image is quite positive among those who are familiar with him, particularly among those who identify with the Tea Party.
Chris Christie, by comparison, draws a more mixed reaction among the roughly three-quarters of Republicans who offer an opinion; 47% view him favorably while 30% say they have an unfavorable impression of the New Jersey governor.