I actually tried picking it up again a few weeks ago. Ever since the game came out I finished the game and most quests a few times, I think I spent around 700-800 hours total until Skyrim was released. After playing Skyrim I can't play Oblivion anymore though. The same reason why I couldn't play Morrowind anymore after playing Oblivion. The new games keep improving, the game mechanics atleast.
I'll have my doubts Bethesda can top the Oblivion Dark Brotherhood questline though, those were amazing.