Continuing our effort to encourage good campaign journalism by praising those who take the time to do it well (don't worry—we slam those who do it poorly), we point you to the Guardian, which has done an excellent job of parsing the very small differences between Clinton's and Obama's voting records. To give you a sample...
Obama voted to ban cluster bombs, "which explode and scatter thousands of tiny weapons over a vast area." Perhaps because cluster bombs were used unapologetically by Israel in its short war with Lebanon, and perhaps because banning such bombs would limit a commander's options, Clinton voted to keep them.
Obama voted to rewrite the immigration law banning supporters of terrorism from gaining entry into the United States, in order to ensure that legitimate refugees were not being kept out. Clinton opposed such a rewrite.
Clinton voted for a measure that would allow law enforcement officials to seize citizens' firearms if they saw fit after a national emergency. Obama voted to let people keep their guns. It was Obama's single "pro-gun" vote in the Senate.
Clinton voted against the confirmation of Bush's interior secretary Dirk Kempthorne, who had a 1% lifetime score on environmental policy from the League of Conservation Voters. Obama voted for confirmation.
There are some others as well. As you can see, these are minor differences. They are overshadowed by many, many more moments of agreement, which tells you that either the two candidates are very similar ideologically, or that they are simply party-line Democrats most of the time. I continue to argue that it is entirely legitimate for the press to report on how the candidates' experiences, character, and approach to government differ, even though such reporting would not be "on the issues."