Ricciardo's really not done enough for me, IMO, to deserve a spot in the Toro Rosso next season. Caterham would be fools if they didn't sign him up over Trulli though, unless Heikki gets pinched by Renault (which seems the only obvious spot open).
So next year we've got:
Red Bull - Vettel/Webber
McLaren - Button/Hamilton
Ferrari - Alonso/Massa
Mercedes - Rosberg/Schumacher
Renault - Petrov/??? (Grosjean/Senna signed to the team at least)
Force India - di Resta/Hulkenburg (which seemingly has to be the case)
Sauber - Kobayashi/Perez
Toro Rosso - ???/??? (Alguesuari, Buemi, Ricciardo & Vergne all signed to the team)
Williams - Maldonado/??? (Barrichello's still technically an option)
Caterham - Kovalainen/Trulli (unless Kovalainen gets signed)
Hispania - de la Rosa/??? (Liuzzi has a contract)
Virgin - Glock/Pic
So you've got Sutil, Barrichello, Senna, Alguesuari, Buemi, Liuzzi and Rcciardo all who were driving this year and only five spots to fill, as well as Grosjean and Vergne who hadn't been driving but present. So four of them will miss out.
Renault have got the toughest option of them all in that they need someone who'll probably only be happy with a one year deal, because Kubica will presumably be back fully by 2013. That wouldn't probably suit Sutil or Kovalainen (if he were willing to move from Caterham). Rubens would probably be good for one last glory ride with a midfield team, but it's whether they'd want him there. I'd guess though that through it all, they'll probably decide to go for Senna or Grosjean, which would be a mistake for me.
Toro Rosso should definitely do all they can to keep Alguesuari. Buemi's done alright this season but that's all he's managed in each of his seasons so far. Ricciardo could fit in there, so could Vergne...I just can't see Buemi on the grid in 2012 though. One way or another, they'll be promoting from within.
If Williams aren't getting Raikkonen, as it seems likely, then they pretty much have to decide between Sutil and Barrichello. You'd choose Sutil over Rubens any day of the week probably, but you get the feeling Sutil would only want to move there if he doesn't get the drive at Renault. At least Williams will have the Renault engine next year, I suppose.
HRT should keep hold of Liuzzi. He's easily been second best out of the new teams' drivers this year (behind Kovalainen). de la Rosa & Liuzzi would make a strong team and then they can maybe bring in a young guy in 2012. I'd certainly trust those two to beat Virgin again, at least.