With Xan Brooks back from Venice and Catherine Shoard home from Toronto, this week our critics look back on the film festivals to pick out some early favourites for Oscars success. Plus: Peter Bradshaw is on the sofa for reviews of ghost bustin', huntin' and shootin' comic-book adaptation R.I.P.D.; and Oliver Hirshbiegel's biopic Diana, starring Naomi Watts in the title role