Iowa

In a few hours the 2016 Presidential primary season will start with the Iowa Caucuses, which could provide close results in both parties.
If the favorites win (decisively) in Iowa, the nominations could be over within four weeks. If not, the nomination contests could be prolonged for several months.

So what do I expect for Iowa?

In the Democratic contest of course Mrs. Clinton is the clear favorite for her party's nomination. But if she fails to win the first contests, it could be possible that - as in 2008 - she again might fail in securing the nomination.
Sanders should be able to remain a serious contender if he is able to come close (or even win) in Iowa, and pulls off a (decisive) win next week in New Hampshire. In that case the Democratic contest could turn into a hard fought race.

(Only) due to her instituational advantages I expect Clinton to win Iowa by 3 to 5 points. O'Malley will finish in the low single digits.

In the wide open Republican field I only expect the following three candidates to have a real shot at the nomination: Trump, Cruz and Rubio.
If Trump already starts winning in Iowa, he might run the table and be able to - nearly - close the deal after the third contest in South Carolina.
For Cruz to have a real shot at the nomination, Iowa is a "must-win" for him, after surviving in New Hampshire, he would probably have to win in South Carolina as well.
For Rubio it would probably be sufficient to start with a third place in Iowa and a second place in New Hampshire. If Cruz and others don't meet the expectations, he might soon be in the role of the last serious contender not named Trump (which could be enough to prevail in the end of the day).

For Iowa I expect Cruz narrowly beating Trump, with Rubio pulling of a strong third place finish. I expect all other candidates to finish below 10% (which would probably doom their campaigns going forward).