I've been where you are. I had herniated disks in my lower back for almost 2 years and I was constantly in pain and I had to watch very carefully what I could do in terms of exercise. It was actually exercise, playing roller-hockey that caused my disks to rupture and I had to have surgery. After the surgery I felt much better and the pain of the herniated disks, not to mention the risk of serious nerve damage, was gone. However, I was not allowed to lift weights for 9 months and the only exercise I would do was core strengthening stuff. This is absolutely crucial as after a lamenectomy your spine needs all the support it can get, which means having a strong core.
Having been there, i would recommend the operation, but you're not going to be able to lift weights or you could seriously injure your spine and main nerves which could lead to all sorts of nerve related problems. You probably don't want to hear that, but it is what it is. You could live with the pain of a herniated disk and the danger of rupturing it and/or causing nerve damage or you could have the surgery, work on your core for 9 months, and be much better off in the long run.
Just my $0.02.