Serious people, you still arguing, Todd Howard himself told us that the MAIN QUEST is 15-20 hours, long, depedning how fast you finish it. There's TONS of sidequest and new features.
Ok, THIS is how hype starts and THIS is how people get all worked up and convince themselves Dawnguard is the second coming of Jesus Christ, and then end up disappointed when it's actually not.
WHERE did Todd Howard say that? I actually went back and watched the E3 vid, found here: http://www.youtube.com/watch?v=7UEQFp4tzQc
At 4:28:
"It's a big DLC, you're looking at 10-20 hours of new content."
Now tell me where the HELL he said "the main quest is 15-20 hours content." Hell, the context of the question he was answering seems to imply he meant 10-20 TOTAL (she was asking him about what would be side-content, presumably, which led him to refer to the general size of the DLC) rather than for the main quest.
So for the love of god, calm the crap down and stop overhyping things.
Not saying it's gonna svck, but I am sick of watching people think everything Bethesda produces is super-awsum and actually twist their own words in their favor. It's one thing to twist a company's words to shine poorly on them, it's a clear sign of blind fandom if you actually twist a company's words to make them look better.