Reading through the old comments on this topic, I was amused by some of the discussion about what being the man who saved the world (as opposed to the man who is now saving the world) can mean for you; and about whether jumping ship is the best way to get a pay rise. I thought I'd shove in some comments on those two topics.
However, the historical fact is that changing ladders remains the fastest way to change your pay by more than 15%.
Not in my experience. I've had bigger increases in pay and benefits when staying with the existing employer than when switching - except that when I switched from academe to industry that was quite a large rise (32%) because academic salaries were terrible. I've had a bigger rise than that without switching employer, but only once; in addition to that once I've had 8 other rises of over 15% from my employer at the time. Apart from the one time mentioned above, I've never had a rise as high as 15% when changing employer (the average, excluding that one 32% as the switch from academe to industry isn't realty relevant to the discussion, is a bit under 5%). If you include times when I've had massive non-salary benefit increases that together with the pay rise made an effective rise of over 15%, that 8 becomes 11.
As for saving the day: it can get you friends in high places, promotions, increased pay, and improved non-pay benefits. It can also cause problems. Once people start assuming anything you are doing must be right you are in trouble: if no-one is properly evaluating and criticising your proposals it's easy for big and nasty mistakes to be missed; and you can find your managers are shouting down any criticism of you and using your reputation to ensure that they get their way (their
way, not yours). Also, it doesn't last: although you may still find some people blindly following you many years later, the company will have moved on and those people will be out of step. Also, something everyone should remember is something that my boss's boss in the late 70s used to tell us all in just about every management meeting he chaired: one Awshit! cancels a thousand Attaboy!s.