I have a friend who was studying medicine. I think the dilemma is the same, though slightly different. He really wanted to specialise, but knew it meant another X years of study on top of the 7+ years he was already spending. I'm pretty sure he ended up going the specialist route, mainly as the life of your average GP doctor is handing out drug prescriptions to people with runny noses
It really comes back to your motivation - hopefully it is not just about the money, but doing something you enjoy...