On the subject of the Clintons' wealth, Kevin Drum notes "Have we ever asked this about any previous presidential candidate? Reagan? Bush Sr.? Bush Jr.? Kerry? (Actually, that's a genuine question. Have we?) ."
To answer his question, the issue about whence came the candidate's money played a major role concerning LBJ, who was a millionaire in spite of never having worked a job (besides brief careers as a school teacher and elevator operator) outside of the public sphere; Nixon, whose ties to Howard Hughes played a major role in the 1960 campaign (after having earlier dealt with a similar controversy involving a black & white cocker spaniel named Checkers); and to a lesser extent, Reagan, whose affluence stemmed from his rather hazy relationship with people like Henry Salvatori and Alfred Bloomingdale. Each had to overcome questions as to the somewhat dubious nature of their wealth before winning the Presidency, so we don't have to resort to Somerbian paranoia about media double standards here.