Almost always go for the higher offer. As odd as it sounds, company value the higher paid person more, it's almost a rationalization on the part of the company.
One more thing: never accept counter offers from your current employer.
One more thing: never accept counter offers from your current employer.
On a slightly tangential note, when I worked for other companies, I was generally regarded as a loyal employee, all things being equal I would rather stay with a company I know, as there are a lot of unknowns in switching companies, I was always upfront about this fact, but I was also upfront about a large discrepancy in compensation being a factor that could compromise that loyalty. Giving people the tools to maintain loyalty helps employers clearly see what they need to do to maintain personnel.