I think I would have to wait and see how they implement Skyrim first. I am the type of person that buys every DLC for games that I love to play. I never bought one DLC for Oblivion. The gameplay failed to meet my expectations and I felt pretty disappointed at the end of it. Having absolutely loved every game in the Elderscrolls world, the "streamlining" of the game left it feeling shallow.
If Skyrim reverses course and makes it feel like a game worth playing, I will be buying the DLCs and be very happy that Oblivion was more of a glitch in the course of a great series. My expectations are much lower this time, so I could very well love this game.