Since McCain is almost definitely the Republican nominee, I'll mention his stances.
Clinton's definitely strongest on women's issues, promising to code Roe into federal law and overturn the global gag rule on family planning/abortion. She voted against the Partial Birth Abortion act (a misnomer, btw).
McCain, would overturn Roe.
Clinton's also the only one of the candidates that will go for national health care.
I wish she was less hawkish and agree with Obama more on stances on Iran and Iraq. He supports diplomatic efforts.
I wish one of the main candidates would pony up and support gay marriage. At least both are in favor of civil unions. McCain would support a federal marriage ban if the courts overturn state requirements.
All 3 are ok on stem-cell.
Snort. All 3 want that ridiculous 700 mile fence.
Both Dems are willing to revise NAFTA. McCain is a fan.
I prefer Clinton on economic stimulus. She's not talking tax cuts, and I like the 90-day moratorium on subprime lending.
I don't know what Obama thinks a $250 tax cut is going to do. That will help slightly in the very short term.
Nobody has anything about restoring the personal liberties taken by the Patriot Act. McCain wants to increase numbers in the military...guess that'll be needed with so many of our soldiers suffering from PTSD. No one has anything to say about additional help for Vets either.
Guns, I don't worry about too much. There's such an underground trade in them that any effort at restriction is essentially meaningless. If you want a gun, you can get one.
On the issues, I have to go with Clinton.