I fucking love the scene of Gandalf removing his grey robe, and how he's kind of got this subtle glow to him. I feel like it's a much more effective portrayal of magical power than some dude flinging fireballs and lightning bolts, just having a guy literally glow with power.
The soundtrack for that scene's also amazing, the choral parts are some of my favorite bits in the LOTR soundtrack
I like the shot of legolas getting a little jolt from seeing Gandalf revealed too, it's probably like looking into a magnesium flare for an elf