Same for me. I bought Dawnguard and Hearthfire but haven't even installed them because there's still SO MUCH to do. I'm at about double your playtime and just visited Morthal for the first time and never really been to Markarth or Rifton.
I really overdid saving stuff for later in Oblivion. For thirty months, that's two and a half year, I played nothing but Oblivion. That's several hundred of hours. And I only finished the main quest in 2008 and did not do a single guild quest and I have never been east of the Niben (except for Cheydinhal and some surrounding area) or south of Bravil.
In Skyrim, I really have to make myself do some "big" quests, I always want to save stuff for "later". Because of this, I still have a lot to do, even after about 250 hours
