You always add to the value by taking raw material to the next level. Just remember that you are attempting to compete with large commercial mills that are probably highly mechanized, probably have their equipment already paid for, and are probably processing many times the amount of lumber that you will be able to handle in a day. They may also operate kilns which generally adds to the value of their finished product. Only you can decide if the additional costs, for your particular situation, are worth the effort. I have seen small operations that will process the raw materials (trees) through to the finished furniture and thereby maximize the profit of the entire (though small) operation.
The end product dictates the rough stages and it will vary depending on the species of lumber and the market. For most furniture projects, 4/4 and 5/4 generally predominates and 8/4 being desirable for legs, work bench tops, etc. oak being different from walnut and cherry.
I would think that the folks that buy your logs would be willing to tell you how they typically saw their logs and that should give you a good idea what your local market is doing.