I think it will be a New Zealand-England final, with New Zealand the most likely winners. Bit of a safe, boring prediction, but there we go.
I was thinking that England might conquer the rugby world again, but the loss of Hartley and Tuilagi is damaging. England did have the best line-out in the world before Hartley's suspension, and Young/Webber are a class below. Still, they have a reasonably favourable draw, and won't be facing New Zealand/South Africa until the final provided they top their group.
And you have to back England to beat Wales and Australia with home advantage, in spite of Australia's recent resurgence. I think Ireland have been somewhat overhyped, while France will inevitably fall somewhere between brilliance and disaster.
New Zealand should be fine to make the final, as long as they don't choke! South Africa aren't in a very good place, currently.
If it is a final between New Zealand and England, I would make the Kiwis 60-40 favourites.