We're getting to be regulars there, have taken two trips this year and one last year, so I guess I'm qualified to answer this now...used to go every odd-numbered year for a while so I knew it was heading in this direction anyhow.
I find it's more or less a matter of how many days you go. My suggestions are as follows:
Two day trip: either get in early one day or out late the other. Make one day a park day and focus on only one park. Use the other to enjoy your resort.
Three day trip: get a park ticket for all three days and make sure it is a hopper. Decide which one to split between the days, but if you want resort time (which I like personally), you'll basically spend the same amount of time at all of the parks.
Four day trip: logic says to hit one park each day, but common sense says to only get three days worth, split one day between two, and enjoy the resort on the first day or the last.
Five day trip: now you've got more flexibility. Four days should be park days. Focus on one park each day, but allow flexibility to go back to one you didn't have time to hit everything at or just enjoy on another.
Six day trip: suddenly, you can slow things down. Five days will be park days. This is one of those times when you can really stop to enjoy something like World Showcase. Alternately, do four park days like above and take one day to remain at the resort (especially if it has a lot to offer like Stormalong Bay at YC/BC or the Boardwalk at the resort of the same name) or add in something like a water park or golf.
Seven day trip: five days at the parks, the rest split between resorts, golf, water parks, Disney Springs, etc.
Regarding Disney Springs: I only mentioned it once here; on the other days, it's a good choice to hit sometime on the way out or back. I've done both on longer trips and actually prefer it, personally, as the opening of a trip. It builds a bit of the excitement without being officially Disney yet if that makes sense. (Yes, I know it's "officially" Disney, but it's not a resort or a park...just a shopping district with some good dining options...)