What's worse: lying about sexual relations or lying about a cia leak?:
The CIA leak was far worse. When Valerie Plame's identity as a CIA agent was revealed, her life, and possibly the security of our country, was put in jeopardy. Clinton's infidelity only directly affected Hillary and Chelsea, and was no skin off the noses of everyone else. 

One reason why the media devoted less attention to Plamegate is because corporations who own the media are major Republican donors.