We were just there this past weekend and ended the day at Epcot on both Saturday and Sunday. Although the "Disney" gift shops were still open, we noticed that the World Showcase country gift shops were all closed by the time Illuminations ended. What we did was slowly make our way out of the World Showcase, taking pictures of the country pavilions lit up and enjoying the empty spots inside them, like the little square behind United Kingdom where the little performance gazebo is, and the area by the fountain in Italy. On Saturday, after leaving the World Showcase we stopped by the little fountain/play area where kids can play in the water and rested. After most of the little kids were gone we took our shoes off and played in the water ourselves...it felt so nice on tired feet and made us feel like kids too (we're 24, 26, 28, 46, and 52). Then we just watched the fountain and Spaceship Earth behind it. Also, we found the area where there are fiber optic lights in the walkway and watched that for a while.
Epcot at night is my absolute favorite place to be, so I enjoyed every second of it and drew it out as long as I could. By the time we got to our bus stop at around 10, the area was clear and we just sat on the benches and waited for the next bus.