There are some very big differences on some very big issues at stake in this election. From Iraq to healthcare, energy to education, and everything in between, the differences are stark. One issue that receives considerably less attention, however, is a little thing called net neutrality. It's an interesting issue in a number of ways because while somewhat technical in nature, it exemplifies some of the more fundamental differences between the two presidential candidates.
First, here is a brief video to explain what net neutrality is, and why it's important.
Barack Obama supports net neutrality, while John McCain opposes it. Well to be fair, McCain has flipped back and forth a few times, but mostly he opposes it. This is a great example of the divergent approaches to policy that Obama and McCain take, however. Obama explicitly expresses support for net neutrality on his Technology issues page. It is one component of an impressively comprehensive federal technology (specifically communications and information access) policy.