I usually spend 6 to 9 in Epcot or walking around the World Showcase. Most of the above mentioned ideas are great but the activities don't usually begin (PO, DTD, Jellyrolls) until at least 9:00 p.m. I say take your time meandering around WS. Admire the architecture, stop in each land and have a little something to eat/drink. A lot of people eat there way around the WS. Personnally I love to tour the other resorts in the evening when I'm not swimming in my resorts pool. Each of the other resorts look so pretty and peaceful when there lit up at night. Another option is to visit the lounges at Cont. (CAlif Grill) or Poly and if MK closes around 7ish (if its closing early) you can have a drink and watch the fireworks going off. Don't forget that there is a movie theater at DTD just incase you would want to see a movie while waiting for the later activities to begin.