The reason there has been so much Obama vs. Hillary coverage is because the race for the Democratic nomination has been closer and lasted longer than any in modern history. Usually both major parties would have decided their candidate a couple of months ago. Also, both candidates would represent a historic first to receive the nomination of a major party, being a black man and a woman. Early on there was pretty even coverage between the two parties, but McCain certainly hasn't gotten the focus that the two Democrats have since he secured the Republican nomination. Now that Obama has secured the Democratic nomination, we should see a lot more even levels of coverage.