Jean's not a slut.
And Emma Frost will take most of them in. Not Wolverine, Colossus, or Cyke. (Wolverine's too violent for Emma, Colossus's ties to the mafia, and Cyke hates Havok too much to stay near him long enough to be at that school).
If I had to bet money, Magneto will get involved in someway. Blaming Xavier's death on himself, for not giving mutants a figurehead to rally around, and we've got the Brotherhood back. And this time no X-Men to fight them.
I would love to have Magneto come back. And Longshot. I love Ultimate Longshot, maybe because I've always hated him in 616....
Xavier dying brings up countless possible stories, and is actually a death I can agree with. Ultimate X-Men without Xavier is far more interesting then with him.
Hell, it will be worth the 2 bucks a month just to see Cyke have trouble keeping up with paying bills and sucking up to the Church of the Shi'ar Enlightenment for them to still pay for everything, even though they have no teacher.
UXM is about to replace Ultimates as the best title on the imprint.