If you can, do the Candlelight Processional. You don't need to have the dinner package but the wait can be long and if the park is crowded you might wait in line and then still not be seated for that show (and have to wait for the next show.) If you were planning on dining at any of the restaurants offered in the package anyway, it would be just as easy to get the package and know that you have seating. WDWIG has the list of restaurants.
If your kids like music then they might be fine; they'd probably love seeing the long trumpets that look like something out of Cinderella's castle! And the living Christmas tree created by the choirs is so pretty. Depending on how busy your day was (HA!) they might enjoy the chance to relax - and you can always leave if they get too antsy. I'd definitely put it on your list though if you've never been.
Is this your first holiday at WDW? If so, don't miss: the Grand Floridian to see the gingerbread house, railroad and enormous Xmas tree, the Beach Club has a gingerbread carousel and I think the Boardwalk has readings of "The Polar Express" on certain nights in the lobby. And every night at Epcot they do a special musical presentation in the area leading from Future World into World Showcase, when the holiday arches are lit up. They coordinate the music with the lights and it's a real treat. Try to take a ride on the monorail thru Epcot after they've lit the arches because you go sort of in between them and it's very cool. Oh, now I want to go for the holidays!!