For the Electrical parade, anywhere along the parade route is just fine--it's in DCA, so obviously you'll be watching it from a different place than eith Fantasmic or the fireworks.
For the fireworks, the hub is the best spot (the area between the parners statue and the castle), but I've seen a lot of rudeness there as well as some very clueless CMs.
For Fantasmic, it's at the Rivers of America in the Frontierland/New Orleans Square area. And if you try an hour before hand for a seat for the first show, you won't find one--try 2-3 hours at least. By 7-7:30 or so, the center riverside section is usually packed and from what I've seen the sides don't have much room either. The second show is generally less crowded, especially on weeknights (sun-thurs) though I've even seen the second show get full (as in an announcement that the viewing area is full) even then.