Hi Slinky

I will try to give you the best advice I can. But please notice that there are many other members of this forum that are much more experienced then me.

In regards to wich set up you are using, it depends on serveral aspects.

1) What is your budget

2) How skilled are you

3) For what purpose are you going to make panoramas?

4) Consider what workflow you will prefer.

You shoulddefinately buy a dslr camera. If it is a nikon or Canon will depend on your preferences. If you already know how to operate a canon, I would stick to that. I honestly do not think there is a huge difference in Canon and Nikon (I know some people will disagree with me on this one)

I think the set up you describe your self with a canon, sigma 8mm and agnos tcpshort is a good choice. If you can afford it you' ll might consider upgrading the camera to a canon5d. It is full screen and youll be able to a 3-shoot panorama. This will effect your workflow. If you are targeting realtors, your time will be valuable and the faster you can shoot the pictures and process them, the more money you make (time is money).

Besides investing in new equipment you should also invest some of your time in improving your skills both behind the camera and  in front of your computer.

If you want the fastest possible learning curve, youll might consider some tuition from Smooth who is also a forum member. Many people in here who have been tutored by him say it is worth every penny. He can also help you with the best possible set up for your needs.

And otherwise this forum is a great place to learn and improve your skills.