I will be be a strong 'dissenting' opinion here. With Epcot being closed... With the it being the so-called kick-off of the celebration... (Cinderellabration is rumored to actually begin very very soon, NOT on May 5th) And with it being the EMH, Spectro, etc... I will NOT be going for my first once-in-a-lifetime trip to MK with my son on the 5th!!!!! We will be at MK on the 3rd, which should be a low-attendance day.... followed by the 4th.
If these are Disney newbies with a young child on their first trip to actually see and enjoy the 'Magic Kingdom'... I am afraid that they will just be lost and trampled, and see nothing but the lines and crowds and more crowds....
For the true Disney enthusiest, like those on this thread, who are able to visit often... Hey, if that date, 05/05/05 means that much to them... that is really great!!!! Go and make your memories of being at Disney on this particular date...
I am just not so sure that these are the memories that the family the OP knows are looking for?
As a first time, taking my child to experience the 'Magic', the 'official presentations', the hoards and crowds and long lines, etc... would be meaningless for my son, now and in the future.
I hope this family plans wisely!!!!
Just my two-cents worth... As many DISers often say, the advice given here might just be worth what you paid for it!