MegaMari. I squee'd like a little girl the first time I got up to the castle stages and saw the quickman death lasers, and buster dueling Yukari is one of the most awesome things I've ever done in a video game. The nostalgia card doesn't work on me very often, but when it does, holy cow does it work.
Mystical chain gets honorable mention, especially with the way the extra stage tweaks off of EX-Alice's original spells.