I start my workout with a 10 minute warm-up on the treadmill. Next I do a HARD 20-30 minutes on the Elliptical. Then, I get back on the treadmill for 10-20 minutes. I end my workout with weights (abs, legs or arms depending on the day).
When I get bored with my routine, I take a 30-45 minute walk/jog outside. It helps me a lot to change things up. I keeps me from getting bored. Hope this helps.