Current poll averages at Real Clear Politics:
http://www.realclearpolitics.com/epo.../national.html
Clinton vs McCain: McCain by 1.6%
Obama vs McCain: Obama by 1%
Clinton vs Romney: Clinton by 11.3%
Obama vs Romney: Obama by 15.4%
Clinton vs Huckabee: Clinton by 9.9%
Obama vs Huckabee: Obama by 16.6%