Absolute power corrupts absolutely.
I don't think you need to be corrupt to have power. Power can be anything. A restaurant owner has power over his employees; hiring, firing, scheduling, etc. Doesn't mean he is corrupt. In fact, many people obtain power, and then become corrupt, so I definitely think power corrupts. However, only if that person lets it.
I find weak willed and selfish people are more likely to succumb. I know I do at first, as I experienced during high school when I became a group leader. I became kind of authoritarian, until I realized what was happening. If you want someone who might not become corrupt in a position of power, look for the person who doesn't want to be in the position of power. If someone desperately wants to lead, red flags should be going off.