Okay, so after ordering a Bare Bones Board, I've been having a bit of a closer look at the schematics, and it would appear as thought the +5V pin that connects to the 'Power strip' (for lack of a better description, the two lines that run along the side of a breadboard) doesn't go through the power regulator, which makes me think that if I were to connect +9V to the DC jack, I'd be getting 9v supplied along the power strip of my breadboard, not the regulated 5v.
I think that either I've missed something in the schematics or it could cause problems for some of the circuits I plan to make.
If anyone could clear this up for me I'd be really thankful 