Remember Dreams Come True fireworks - my opinion is very different from Wendy's as I think you have to see the fireworks from the hub. It is an incredible experience, and the fireworks show was designed to be viewed from there because of all of the special effects on and around the castle. Totally worth it IMO to deal with the crowds.
I have seen the fireworks twice from the hub, and the spot I liked best is out in front of Refreshment Corner aka "Coke Corner". If the hub was a clock and the castle was at 12:00, we were at about 7:30-8:00. It was a great spot to see everything. We got there 60 minutes early.
Fantasmic - we like to get down near the water in a sitting area, which can be done pretty easily on nights when they have two showings and you go the the second one. You can get a good spot 30-40 minutes in advance.
POD - saw this twice as well. I am not sure there is a best spot, it depends on the show stops and what floats are nearby. We avoid Main Street for this and saw it both times back by the Matterhorn area.
Electrical Parade at DCA - only saw this once when it was at DCA, and we saw it from Sunshine Plaza and that was fine.
BPB - Saw this once from Sunshine Plaza as well. Our spot was not that great because we wanted to scoot over to Calif. Screamin after the Bash, but it was still fine. You can also see this over by Paradise Pier.
HSM - too new - haven't seen it - we plan to see it in June