I've often found when making choices like this one it helps to keep in mind that the choice is not forever. It could be but it doesn't have to be.
Don't over analyze. Go with your gut and what you think you would enjoy most (from a work/employment standpoint) and don't look back.
And do not factor in the GF. Sounds like she's a recent addition. And you'd kick yourself if you settled because of her and you broke up soon after.
