Forget salary, it's not important.
When you start your career, gaining relevant experience in your field is the most important thing.
What good is it earning £25k on a finance grad scheme when you would rather work in media?
That's the decision I faced when I graduated, so I turned it down and took something offering £18k instead.
While I don't earn as much, the smaller company let me take charge of some monthly digital media workshops where I teach fairly large companies (turnover of £100m +) about social media, copywriting and video production.
To me, that experience is worth far more than just coming out of uni on £25k+.