I absolutely would not skip Epcot. There's a ton of things for kids your children's ages to do. For rides- If they are tall enough, and for sure your 8 year old should be, Soarin' (Land Pavilion), Test Track, and Mission Space (if you are concerned about the spinning version, the non-spinning version is still really cool). My younger child (she's almost 10, but the size of most 7 or 8 year olds) is timid with thrill rides, but she absolutely loves these three rides, and these are must-do's for her. There are also some really tame rides she loves-I can't tell you how many times we have done the Imagination ride with Figment, and the Nemo ride in the Seas Pavilion. There is also an interactive show with Crush that is cool. Spaceship Earth is now interactive, and there's lots to do at the end of the ride. There are lots of interactive things for kids to do, including the Kim Possible game. Every country has a kidcot table, and they can do a craft project and talk to someone from that country. Definitely do Epcot, at least one day, if not two. We always have park hoppers, so we get in early one day, to do the rides, and come back for an evening, to see the fireworks and have dinner. Personally, I would do DS for one day, and Epcot for two, if you have to choose. When my kids were those ages (they are three years apart), we always park hopped, and took rest breaks every day. We would go to one park in the morning, split after 4 hours or so, maybe after lunch, take a break at the hotel and relax, then go back for a few hours, perhaps to another park. Epcot was often our late day park, because of the dining options and evening atmosphere, but we would always go early there at some point, to get the rides in.