This is a very easy question, but it's also a tough one. There are soooo many angles you can look at this from. Emotional states, do you have children who have a preference or get scared easily? Do you mind risking getting a fast pass for a particular seating area, waiting all evening for your shows, or spending extra money to get a decent spot and save a small bit of time waiting? The pro's and cons are endless. I know that people may have a preference over shows, but also here is a question... If everyone had the option of getting the best seats for each show and not having to spend extra money and wait for up to 2 hours, do you think they would enjoy it more?
My personal fav's in order...
I kind of have to say Fantasmic. I am all about "Classic Disney", and they way that they put it together with all their props blows me away. Having children too I find that they prefer seeing Fantasmic as it's more "Interactive" in a way, there is something for both boys, girls in a realistic sense, and there' just so much more going on to see. I can also stand in Frontierland and watch the fireworks from that area after Fantasmic is over. So I dont feel like I am missing much in the way of shows. I feel like I can pack more into a one time shot deal. I also really enjoy Big Thunder Mountain at night time when the fireworks are going off.
Having only done the World of color by dinner package (And we always do one or two dinner packages a trip) it comes in a close 2nd. It's new, it's very colorful, it incorporates characters & music you don't normally see or hear anywhere in the park. It can be intense but I really enjoy seeing certain movie scenes that I have grown up to love put into a show. The only thing I dont like is having to work my whole evening around that one show. However you do the same thing with all the major shows... Even Aladdin you have to line up at a decent time to get a non nosebleed section.
So that brings RDCT to a 3rd option. I do love this show, and it's meant to be seen in front of the castle where i've seen it multiple times. It's gorgeous, it's emotional, but I would choose getting a better seat for Fantasmic over seeing the Fireworks as I can see the works from another area of the park.