The best exercise to do is whatever exercise you enjoy. Most people like variety and will run one day and play basketball the next day. Find an activity that you enjoy and stick with it.

The best time to work out is, again, whatever time of day you like. Some people are morning people and they usually have no problem with going to the gym at 0600, others like to workout at night. What time of day you workout isn't important, what's important is how you're working out and if you're getting enough nutrients and rest.