1)
http://www.youtube.com/watch?v=NHRPJM2yxR0
Kodomo no Omocha - William Tell Overture : Craziest AMV ever
2)
http://www.youtube.com/watch?v=cOOU5Yr_ynU
the Ghibli Universe and a song that fits perfectly.
3a)
http://www.youtube.com/watch?v=Xo6GZsaQKa4
Another greatly animated and very funny AMV by Kevin Caldwell (who did the first one). 3b) With a terrible song, but by the same guy and about the same anime :
http://www.youtube.com/watch?v=Xo6GZsaQKa4
Damn, must rewatch Golden Boy. I only saw it once, dubbed in french and 8 years ago !