Andrew, I would hope that Virgin jumps into one of the big three, but with for of the major players merging or already merged. It might make sense for them to create a new alliance. I would be far more apt to fly OneWorld, if Virgin got into bed with them.
tassojunior
I think Branson has already said Virgin is joining an alliance by the end of the year. They're partners with several *A lines including CO & US.