Do you like to train first thing in the morning? Are you up and at the gym before daylight, even beating the birds before they're out of bed?
Or, do you prefer to alleviate the stress of your day, taking out your frustration on the weights? Maybe you like to work out knowing that your bed is coming up right after, knowing you'll get a good nights sleep?
Whether you train in the morning or the evening, the important point is that you are training. Find the best time that works for you, and stick to it!