Been there for 5 NYE's everyone in Epcot, if we go again I am sure it would be Epcot again.
Don't go expecting to do lots, Soarin's line exceeded 6 hours this last NYE, just go for the atmosphere. We get to "UK" for 7pm(midnight at home) then watch 7:30 fireworks and out for a meal. We then used to goto DTD to see PI firworks but no more.
After spending 5 Xmas/NY there we are giving that time of year a miss for a few years, this time was busiest we have encountered.