Firstly welcome to the world of aviation.
This is a question that everyone wants to know the answer to, and it is quite difficult to answer. You must research, which I am sure you have, what options are open to you when you have finished.
It is not unheard of to step straight into an airline job after finishing your training. However, on saying that, these people who do this tend to be a minority, simply because of how competitive this industry is. With the airline I work for, they are taking people straight out flight school, and poping them in the right hand seat of an Airbus, so it can be done, and has been for many years.
Its a good idea to have a plan B and maybe even C up your sleeve for when you have finished, and build this into you financial planning.
From a personal point of view, I think it is very important to stay current. Now, whether that is instructing, banner towing, being a tug pilot, doing aerial photography, it all helps and it keeps you in the loop. I was an instructor, and still am, and thought it was a great way to keep current. It is one of the best jobs I have ever had, and it certainly helped to keep me fresh and in the loop. On saying that though, its not everyones cup of tea, but I certainly enjoy it.
All the best with it, and most of all enjoy it, its a lot of fun.