When I was growing up, dad was home from work by 3 and would have dinner ready by the time mom got home, around 5:30. When I got to high school and started doing marching band and had to be at games, we'd eat a bit earlier to get there on time.
In college, it was whenever band or orchestra was over. Mondays, Wednesdays, and Fridays the band members would all get back to the dorms around 5:30 and we'd all go down and eat (we lived on the fine arts floor, so we went en masse), on Tuesdays and Thursdays it was closer to 6.
When I moved out of the dorms, it was whenever I got home and cooked, and depending on classes and jobs it could be anywhere between 5:30 to 10.
Now my family has a standing dinner date on Mondays for 5:30. The rest of the weekdays it depends on when BF gets off work and heads home, it could be anywhere from 6 to 9, depending on how busy he is. Weekends it's whenever we're hungry, usually between 5 to 7.
Now that I write that all out, we NEED to get on a better meal schedule.