If you are still undecided about who to vote for in the upcoming presidential election, let me try to help out in terms of issues.
If you are pro-choice you should favor Obama/Biden; if you are anti-choice you should favor McCain/Palin. This is a HUGE issue this time around because the right has been successfully loading the Supreme Court with right wing judges. A vote for the Obama ticket will probably cause at least one of the SCOTUS judges to step down (Stevens) and be replaced with a like-minded liberal-leaning judge. A vote for the McCain ticket may allow McCain to replace a liberal judge with a conservative one (Stevens would have to die, doubt he'd step down if McCain wins)... and that puts the future of Roe v. Wade in doubt.
If you are concerned about Social Security existing in a form similar to the way it has existed since its inception, then you should favor Obama. If not, McCain has clearly communicated his dislike of Social Security.
If you are interested in some form of universal health care you should favor Obama. He has a plan that could be implemented in short order if the country is behind it (which most polls show it is). If not, you should favor McCain. He has no plan for universal health care.
If you are in favor of continuing our occupation of Iraq, you should favor McCain. He has publicly stated his willingness for our service men and women to remain there almost indefinitely. If you are interested in ending the occupation, you should favor Obama.
If you think war is solution to the global issues we are facing, you should strongly consider McCain. If not, you should strongly consider Obama.
And if you are in favor of providing for our brave service men and women after they come home and need some help, then you should favor Obama. If not, then McCain is your man.
If you are not concerned about the economy and think things are going along nice, you should favor McCain. If you think changes are needed, you should favor Obama.
Indeed, if you are a fan of the George W Bush years, you should favor McCain. He has voted almost in lock-step with the Bush administration over the past 8 years. If you think we need a dramatic change from the Bush administration, you should favor Obama.
If you favor a religious view of political issues, well, both seem to favor that more than I would like. The addition of Palin to the McCain ticket tips the god-scale in his favor. If pentecostal religious fervor frightens you, favor Obama.
If you want a diverse group of people running the country, both candidates have indicated that they will build a staff of people who are not yes-men and would probably look to offer positions to people from both parties. Personally, I do not trust the Republicans to do that. After all, the last guy ran as a "uniter not a divider" and promised "compassionate conservatism" - both of which were lies.
Speaking of lies, if you are interested in having liars running the country, favor McCain.