Looking at the squads that have come out so far, I think Australia will be very hard to beat. They have nice blend of experience and youth, fast and spin bowling and powerplay hitters and finishers. However they do seem to be in the tougher half of the draw. Think Sri Lanka and New Zealand will be the Aussies main challengers. I've been very impressed with New Zealand lately, and Sri Lanka seem to win important games. Especially in familiar conditions.
As for England, I don't think we have a hope. Without Pietersen, we may even finish 5th in the group. Lumb, Hales and Wright isn't too bad as a top 3, but why we keep playing Root in the middle order is beyond me. Morgan and Buttler will have to have a stormer in order to get out of the group. Even if that does happen, our bowling is so bad it's untrue. I've supported Dernbach for a while now, but teams have definitely worked him out. His 4 overs are guaranteed to go for at least 45, so you're already on the back foot from that point. To make matters worse, Parry and Tredwell are very average spinners. It could be carnage.