I have to respectfully disagree with Leazel in that Minnie & Friends gets a lot of mention here on the board. People
love Minnie & Friends. M&F clearly has the most characters out of all the character meals. The thing that seems to be a recurring complaint/observation is that the food at Minnie & Friends is not always that great or fresh. Of course, there are folks who love it, but more often than not, we have had seen comments that the food was sorely lacking.
Here is our character meal photo thread, so you can get a really good idea of which characters are at which meal:
http://www.disboards.com/showthread.php?t=2234435
And here is a link to Page 23 of Disneynerd420's Trip Report (below). Scroll all the way down. Post #338 and Post#339 show you pretty much all that is available at Goofy's Kitchen for breakfast/brunch, which is a lot. Goofy's has an all you can eat buffet, and it has the widest variety available of all the character meals (hence, the higher price tag). I love it there, and have been eating there for years. The food quality and assortment is really good, and I like the characters (Goofy, Chip, Dale, Baloo, Pluto, etc., etc.). I have never found it to be too loud, and I have never had a bad experience there. If there were fewer characters, the food more than made up for it, but usually it is a good combo of food and characters. It gets active and Goofy "bakes" with the kids and dances with them for a few minutes here and there, but otherwise, I never thought it was too bad.
http://www.disboards.com/showthread.php?t=2268157&page=23
I have never eaten at Ariel's Grotto, so I cannot speak from experience, but it is all Princesses - no fuzzy characters. Goofy's has a mix of fuzzy characters and Princesses/face characters. Ariel's does not serve buffet, but for breakfast it is food served family style. Lots of DIS-ers love Ariel's. Both are in the higher price bracket of the character meals and are considered "premium dining."
So it really just depends on what you think your kids will enjoy.
Surf's Up with Mickey is the only meal where you will find Mickey and Daisy Duck, along with Stitch and some other characters.
Storytellers Cafe has a menu or a small buffet option, and features the woodsy/jungly Disney characters. It is probably the most quiet and laid back of all the meals, which lots of folks prefer in comparison to the high energy fun of Goofy's, Minnie's and Surf's Up with Mickey.