Actually, there is one scenario where I wouldn't mind Beast comming back. That's if he came back as Dark Beast with help from Mr. Sinister or Apocalypse. Any other way, I agree with you, Baxter.
Carnage - He's had his return already, with a different spin. I honestly don't like Ultimate Carnage (Carnage II was a better incarnation than the first, but still), and I hope we don't see him again for a long while (If at all).
Venom - Venom's story was wrapped up nicely in the USM game. I could maybe see him returning later on down the line, but I want it to be awhile. I've had my fill of Ultimate Venom for the time being. I could see him in a milestone issue, like 150 or 200.
Green Goblin -I'd love for GG to return for a Double Goblin arc. Have both him and Hobgoblin break out to cause some havoc. I'd love to see Peter try to take on Father and Son at once. It'd be great. Maybe have Harry turn on Norman, for a Goblin vs Goblin throwdown at the end. I definetly think we'll see more of GG. Maybe not too soon, but definetly before Venom or Carnage.