I really hope it will be Tsonga, because with the crazy crowd support he would have he could actualy make the final competitive... and even memorable, which has not been seen for a VERY long time at RG (maybe Agassi-Medvedev, though even this one I didn't like).
However given the current form of each player Ferrer looks the most likely finalist. I would put Federer in 2nd, since even though it is a 50/50 against Tsonga Jo would have a much harder time dealing with Ferrer and the pressure. As for Berdych/Gulbis, given their horrible draw I don't think either will have enough in the tank to beat David in QF. I wish I were wrong though