We have a concept 2 rower. Phenomenal workout. Whole body plus cardio. I would do some abs if you have low back pain too
Air Assault Bike....aka "the Devil's tricycle". It will put a hurting on you, not bad on the back.
Thanks for the suggestions. I'm pretty much good with abs. I've kinda slacked off since about July when we started the new shift, but when I get my weight workouts in, I still do 100-200 abdominal exercises. I was more in the 300/week range. Back issues come and go, and about twice a year I over do it lifting something heavy and have serious issues that usually go away within 24 hours. I just need something where my back stays neutral and straight up and down for the most part. I really would like to get more stretching in to increase flexibility. I'm hoping that would help with the back issue.