No. 1: Laura
Credit: Vervegirl TV
Played by Elise Bauman, Laura is a tiny but passionate university student who believes in righteousness and saving her school from those who would harm it. Her character comes up with many convoluted schemes, some of which succeed and some of which do not, but all are executed with the same zest and desire for triumph over Evil. A self-styled detective, she jumps straight into action as soon as someone she cares about falls into trouble, without even thinking about the possible consequences to herself.
Plus, she owns a TARDIS mug, which just gives her even more awesomeness points.