If the LibDems learn anything from tonight's results it is that Labour is not as weak as everyone though three weeks ago. There is loyalty within the ranks and they are still viewed as the legitimate opposition to the Tories.  LibDems didn't show any sign of taking their place in that equation tonight.  

Brown is ruined and so are some of the other faces of NewLab that won't be missed.  The UK voted for part of the Labour platform.  A coalition needs to determine which parts of that platform can move forward and which ones cannot.  Does anybody seriously believe that Cameron will negotiate anything?  Any coalition partner will either be run over or shown to have made an egregious error three months later when they have to collapse the coalition.

Labour won enough votes tonight to avoid the appearance of illegitimacy provided that Gordon Brown is no longer PM.

And a large majority of the UK, in the popular vote, chose to vote for someone other than the Tories.  This argument depends on support for PR, which Labour is already going public with.

Clegg + Brown - old and smelly.
Clegg + Cameron - Clegg loses around half his supporters and not a few of his MPs overnight.
Cameron + Brown - just no.
A.N.Other + Clegg + PR - Clegg might go for this as a caretaker government while another election with PR is set up. It would give ANOther a change to establish themselves.

Brown is Labour's biggest liability, so a fresh face might swing things in an interesting direction.

But I still worry about Clegg + Cameron, and some pious self-serving nonsense about a government of stability in these difficult times, etc.