Dave,
Make your client a partner. I bet you guys really enjoy each others company. Give the client some stock. A good reference. A test bed for version upgrades. Ideas. You and that client built the system together. But you do own it. If the client was an asset while you were building it - he'll prbably be a great asset as you campaign your system. If you guys already trust each other - take advantage of it.

>Dear John, Jim, Rip, Arto, and Thomas
>
>I guess I was hoping that everyone would overwhelmingly convince me to go sell the software as is, since I'm in a tight financial situation. However, my financial situation has nothing to do with what is considered ethical. Ethics has all to do with what is fair. Yes, I'm pretty sure that I could legally sell the software without his permission, since he agreed that I own all rights. But, I don't think this is the ethical or right thing to do. If I was in his shoes, I would be be pretty upset.
>
>I've decided that If I decide to sell the application, I will modify it so that it doesn't step on the toes of my former client. The main value to my client is the analytical studies that I've included as his reports. I'm going to remove these reports from the application. If other doctors require studies or reports, they will need to send me their specifications, and I will custom create their reports/studies. The remainder of the application is pretty generic from my perspective, and could be applied to other medical specialties. So, my selling that portion of it will not interfere with my former client in any way. Actually, I will be offering customization of this portion to each doctor's specific needs.
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>I understand the viewpoints of everyone who responded, but I think it all comes down to what each programmer personally feels is the right thing to do in a specific situation. So, I'm gonna go down the middle and still sell it, but make sure it doesn't adversely affect my former client. I may even ask him if he would like to partner on this.
>
>Dave