JB, I have to disagree. It seemed to me that the OP was concerned with cost and if that is the case, then learning on a cheap Graflex is very cost effective. Also, it sounded to me that he was mainly interested in studio work and can just as easily learn the basic elements with roll film as with sheet film. Why practise lighting with an 8x10?
If he has money to burn then, sure, get an 8x10 and have fun.