On the Democratic side Hillary Clinton continues to be completely dominant. 67% want her to be the nominee, compared to 12% for Joe Biden, 5% for Elizabeth Warren, 3% for Mark Warner, 2% for Andrew Cuomo, and 1% for Cory Booker. Clinton's dominance is near total- she has an 82/9 favorability rating and polls over 60% with liberals, moderates, men, women, young voters, and older voters alike.
In the instance that Clinton didn't run, Biden would lead the field with 40% to 13% for Warren, 8% for Cuomo, 5% for Martin O'Malley, 2% each for Booker, Warner, and Kirsten Gillibrand, and 1% for Brian Schweitzer.
If Clinton and Biden both didn't run it's pretty much completely up in the air- 47% would be undecided with Warren at 21%, Cuomo at 11%, Booker at 8%, O'Malley at 6%, Gillibrand at 3, and Schweitzer and Warner at 2%.
Clinton leads hypothetical general election match ups in the state by similar margins to Barack Obama's victory there in 2012. She's up 4 on Jeb Bush and Mike Huckabee at 45/41 and 46/42 respectively, 5 on Rand Paul at 47/42, and 6 on Chris Christie at 45/39. Her average lead of 5 points against the trio of Bush, Paul, and Christie is down from an average lead of 11 points against them on our July poll. That's a similar decline to what we saw for Bruce Braley in the Senate race as the political climate has worsened for Democrats in the last half of a year.
http://www.publicpolicypolling.com/main/2014/02/clinton-huckabee-hold-early-leads-in-iowa.html