I am currently using Cakewalk 9, and it is still walking. I am looking for an update to put me into the current century! My first inclination is to go with Sonar because of brand dedication and possibly reducing the learning curve, I do not handle curves well which is why I have not upgraded in ten years. I my pre laptop days I would get my hands on it about once a month and have to do more relearning than recording. Now that I have a laptop, an M-Audio Oxygen 8 and an M-Audio Fast Track USB Mic/Guitar box I am looking forward to at least being able to create rythym tracks while I am out on the road.
My second inclination is to go with Acid Pro or some comparable Sony product to Sonar, so that I can seamlessly integrate it with my Sony Vegas video editing software.