She has at least a 60% chance.
Barring any new real scandals that will stick she'll sail through for the Democrat nomination.
Right now all the would be Republican candidates are attacking her but eventually they'll have to turn on each other in order to become the Republican nominee.
Once you get to the general election your rival's words are used against you and if someone catered to the extreme right or left in order to win their party's nomination it's a challenge for them to win the "swing vote" or independent voters who prefer a centralist candidate.
At this moment Hilary doesn't have any rivals in her party so there will be less pressure on her during the primaries to compromise.
Her husband, Bill Clinton is also still very popular, and most of the people who are unhappy with things in the U.S. personally blame Obama and not his party. Some people see it as with Hill you get Bill.
Republicans will have to overcome all the "other issues" that divide the nation. (Abortion, Immigration, Marriage Equality, Cutting or modifying Social Security, Medicare, and Climate Control)
It's easier to do that when their is a crisis or economic disaster. However if things remain as they are; lower unemployment, stock market highs, low gas prices, and reduction of the deficit; the economy will be a non-issue.
Having said that it is uncommon for one party to hold the presidential office beyond 8 years! We often turn to the other party after a two term presidency. George H.W. Bush was the last to do so after Ronald Reagan left office. Generally speaking people vote according to their pocketbook. They want to believe the actions of a president determines their net worth.