Check this out:
Body for Life
This will help point you in the right direction. The workouts are under an hour and provide the right guidance on how to execute the exercises for maximum effectiveness.
There's another side to it that many people fail to consider. All the reps in the world aren't going to provide you a defined look if you don't also address your diet. Healthy nutritional planning is a key part of achieving a well defined look.
Hope this helps.