I used to do all my workouts in the early morning, but lately, mostly because of insomnia, I'm just doing half in the morning. The other half of the time, I'm choosing to sleep an extra hour and a half so that I can get through the day. (It's funny - I can be wide awake for 2-4 hours between midnight and 5:00 a.m., but starting from 5:00 a.m., if I've been awake, I crash and sleep really deeply for a couple of hours.) On those days that I sleep in, I do my workout after work and after I pick up my 7-year-old daughter from school. I make her dinner, and while it's cooking I have a quick snack, select my workout, get changed, get hydrated & get ready to do my workout. As soon as I serve her dinner, I start my workout, usually between 6:00 and 6:30. She is allowed to interrupt me if she needs more food, needs help in the bathroom, etc., but for the most part, I can get through my workout with no problem. She is a slow eater and she loves to read a book while she eats her dinner, which is fine with me. I'm generally done by about 7:15, which is when DH gets home.
On days that I am able to work out in the morning, DD and I eat dinner together and we talk about our days. I think this is important, so whenever I've had enough sleep, I make sure I get up and get that workout out of the way in the morning - that way we have some togetherness in the evening.
I would not be able to start my workout as late as 8:00 p.m. - my motivation is pretty much gone by then and I'm ready to settle down for the evening. The trick for me is to start preparing for my workout as soon as we walk into the house, so that I can be working out within half an hour of getting home.
Stebby