so im going to roll down my drive way (its a hill). as long as i'm straight it shouldn't be a problem using my front break right?
go take an msf course....seriously you'll learn a ton.
Using your front brake is fine in a straight line, hell its fine at any time if you're good and smooth on the brakes.
If the bars are turned and you arent super smooth on the front brakes the bike is going to want to fall over in the direction that the wheel is turned, as has already been mentioned.
There is a whole skill to using your rear brake while slipping the clutch during low speed manouvers, if you just try and take little bits and pieces of information and try to make sense of when to use them you're probably going to end up hurting yourself.
The msf course covers most if not all of questions like how to use your brakes properly.