The only ones there now that I've actually seen in person are IllumiNations and Fantasmic! so the other three are ranked off of Youtube videos and my excitement (or lack thereof) about seeing them.
1. Happily Ever After (even on Youtube it blew me away. Cannot wait to see it in person.)
2. IllumiNations (I just love the music and love Epcot World Showcase in general...good "feels" with this show)
3. Star Wars (the old Star Wars show would outrank IllumiNations and come close to HEA, but the new one doesn't look as good to me, and I love Star Wars).
4. Fantasmic! (It has been a loooong time since I saw it, but I remember wishing we had gone to a different park to see different fireworks)
5. Rivers of Light (I keep trying to watch it on Youtube and it keeps putting me to sleep. I like explosive, exciting nighttime shows, and this is not that. I'm sure it's pretty, but not something I'd go to great lengths to see.)