Our strategy when we first arrive at Epcot is that my husband walks quickly over to Test Track (40' height restriction) to get fast passes while the rest of us slowly go to The Land where we join my out of breath husband to ride Soarin' (40" h.r.) -- sometimes we even try to ride it a second time. From there we enjoy other great offerings around this area: Journey into Imagination (fun things to play with after the ride - remember email addresses!), Honey, I Shrunk the Audience, The Seas with Nemo & Friends, and Turtle Talk with Crush. This isn't everything in the area, but these are our must-sees that I'd recommend within your 1 day visit.
Depending on the time of our fast-passes, we began wandering toward Test Track by stopping at MouseGears for some shopping and Innoventions East/West for some playing around. My favorite is a chance to send email postcards to family/friends as well as the chance to ride a Segway (must be 16 yrs. old). I should caution you that it is easy to lose track of time in Innoventions. If we are running late, we go first to Test Track.
We are a family that skips Mission Space (44" h.r.) after it made my husband pretty queasy years ago - yuck. However, it continues to be a favorite ride of many; so it you are game and the line is short, the adults may want to give it a try (it does have 2 levels of intensity to select from). The exit area of the ride has a fun play area for little ones as well as many interactive electronic games (more chances to send fun emails!).
By now, it is probably time to head toward the World Showcase, but first we make a stop at Club Cool for Coke samples from around the world. If you want to play a joke on someone, encourage them to taste the one called Beverly.
If you do stay for EMH, you will have more chances to enjoy many of these attractions and perhaps have a chance to squeeze in a ride Spaceship Earth.