Can I dig this thread up again? Because I think it's a great idea and I would hate to see it die...
These two AMVs are pretty similar--I think they even use a few of the same clips--but they're also pretty well done:
Feel the Mambo - mix of anime
Shake That! - mix of anime
Also I used to love this when I was younger--uses "Still Alive" from Portal credits
L's Still Alive - Death Note spoilers, I think
Finally, somewhat shameful plug for my own (very first) AMV. Is that allowed?
Spring - Secret World of Arrietty - has some spoilers