A case for instant run off voting?

If a candidate for president does not get at least 50% of the Electoral college votes they don't win and congress must cast a vote. Something worth thinking especially in light of the fact that Michael Bloomberg will probably get at least 1 EC vote as Maine splits their votes and Perot was most successful in Maine.

If we aren't satisfied when 50% of the official voters for president can't agree why are we satisfied when 50% of the voters can't agree in other races? At the same time if we are satisfied when 38% or 42% of citizen voters cast a vote for the leading candidate in races for Governor or US Senate why aren't we satisfied with the citizens choice when it comes to president? Whats wrong with consistency?