Well, in terms of delegates, Paul, Santorum, and Romney all tied first with 7. Perry and Gingrich got 2 delegates each. Bachmann didn't get a single delegate, Huntsman didn't run in Iowa (although I think he got a few hundred votes, anyway).
Gingrich will drop out after South Carolina, and he will endorse Santorum. Santorum will not win another state. Bachmann will either drop out in the next couple of days, or she will drop out after New Hampshire, she too will endorse Santorum. Huntsman may drop out after New Hampshire unless he does exceptionally well (polling third, which just won't happen), Huntsman will probably endorse Romney, though it wouldn't be the biggest shock to see him endorse Paul. I'm pretty much certain that Perry will drop out either after South Carolina or Florida, and that he will endorse Paul - Texan, pro-life, border defence, Perry admitted that Paul swung his opinion on the Fed.
The race is going to thin out pretty quickly, between Paul and Romney. Paul may pick up a handful of states, but Romney will win. What will be interesting, however, is what happens after Paul drops out of the race. I don't think he will run third party, per se, but his endorsement of Johnson will certainly boost Johnson's standings in the final race. Definitely taking the independant, red Dems, and libertarian Repub vote. Will probably result in a Obama marginal win.
Let's also not forget the Americans Elect project. Paul seems to be winning that, anyway, which means he might end up on the ballot on every state without running third party or winning the nomination. If Paul can capitalize on this, we will see a President (most probably Obama) going into the White House with way less than a majority vote. Politics in America will have radically changed.
There's also the vote for a third of the senate, the whole house, and 13 governors on this date. It could be a good night for Libertarians/Tea Partiers, even with an Obama win, setting the stage for a great 2016. With Obama definitely gone, and the two-party grip ceasing, something magical can happen that night. Hopefully Rand Paul will run