I think someone might have already posted the link, but Al Lutz over on MiceAge had a article about June 17th being the day that DL execs think will be totally insane (because of passholder allowances). They are making the employees park at Anaheim stadium and leaving their lot for overflow.
As someone said previously, if I was going to go any of the days within a few weeks of opening, I would go that first day, because then at least you could say you were there for the opening. I would get there as early as you can drag your butt out of bed, and as others have said "treat it like a party" you can say "I was there for the opening day" at least that way, and tell stories of how crazy it was. If you go the 17th it'll be just as bad, and your story will be, "we went the third day it was open"...much worse story!
Me, I would likely want no part of any of it. I get no kick from "bragging rights" nor pleasure from the party atmosphere and crowds. I'm a WDWer that prides my self in planning around the lowest crowds and in never waiting in line more than 5 minutes. We are taking our first ever DL trip about 5 weeks after opening, and I am hoping the insanity has waned slightly enough that its not just massive lines and crowds from the minute they open. If not, hoping to learn best strategies from those that go before me. If I had the choice, I would be waiting 4 months, or maybe a year to go. But since we are going anyways...I can't wait!