Since I can't honestly say that Oblivion was a great game, even thou I spend hundreds of hours on it, I try not to get my hopes up this time around. When I stopped playing Morrowind I did it because I did everything imaginable several time over and it was just time to move on (I recently started playing it again btw, with 10 gigs of mods for a refreshment and it's a blast!
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When I stopped playing Oblivion it was because I cough my self on a thought that I simply don't want to play, I rather go read, chat or do just about anything else, but not play it. For a moment there I even got a fright that I finally "outgrown" playing altogether, but thankfully I got Mass Effect, just out of curiosity and found out that I still can sit 20+ hours playing and be ecstatic about it.
So since the whole Oblivion experience nearly put me off of gaming at the end of it, simply because it was dull, stale and frustrating after the novelty of beautiful graphics (that had many faults when you looked closer as well - like static, bulky hair, unmoving cloth and so on) [censored] off and a couple of good quests that it had where done, I am very courteous about Skyrim. And don't even start me on Fallout 3 (and no New Vegas does not count, it's not Bethesda that made it)...
In fact SI is the only thing that makes me hope that Skyrim would be a great game - it showed that they still got it in them to make an interesting game with interesting setting and fresh ideas. I sincerely hope that they'll fix the issues Oblivion had, both gameplay wise and for modding purposes, add a SI spirit to making quests, characters and details. And that Skyrim would be awesome and a rebirth of the series including both Oblivions graphics and accessibility, and Morrowinds depths and attention to details, but I'm reserving my judgment until the game actually comes out.