Well honestly, The Dark Knight was a good movie, but it wasn't that great that it should've been winning many prices. 2 Oskars is good for that one, although it was obvious Heath Ledger was going to get the one for supporting actor. Actually all of this years oskars have been pretty predictable, i got 19/24 right (no way i could've known best documentary and the likes, never even seen those).
True Slumdog is overrated, but same as in other years, it was simply the logical choice. Benjamin button was just too mediocre in any but the technical aspects. The truely great movies never get mentioned in the Oscars anyway, so who cares about these...