Championship Sunday, Who really are the underdogs?

Always an upset but who really are the underdog teams?
Is that truly the away teams (lower seeds) or are we looking at the line? 
Does Vegas really count?

So there is ALWAYS always a weekly upset for these playoff games.  

There are many variables normally home team is favorite, but not the case for Falcons (13-3) nor did any ESPN crews go down to cover this week in Atalanta, which deams to the possibility of ATL to surprise everyone and beat SF (11-4-1).  Did Seattle show them the keys?? or did Green Bay?  Everyone has been Kaepernick crazed this week, but can someone do that 2 weeks in a row?

With that said, is that really the upset?

Or does that make room for Baltimore to play upset kings in Foxborough?

Or if you consider highest seeds then you could place host teams as favored.  
Which does open a door for Ravens (10-6) to beat Pats (12-4).  Been a crazy week of preps and analysis. So I think highly unlikely that the media would have a Harbaugh SuperBowl - not to say I wouldn't like to see it.

Again, I can't seem to pin point the upset, but I think I may go outside the lines and say
Falcons and Ravens come out as winners today.  By the way, this has no bearing on my heart wishes which would be a Brothers 47th SuperBowl meeting.