I think it depends what you count as scientific computing. I'm an engineer at an industrial plant and like you for offline non intensive stuff when I have to knock up a prototype fast I use SAS mostly because it has good integration with databases and I can crank out code very fast using it.

My housemate is a Math/Stats person he works in finance and uses R for much the same reasons.

Maybe Python is useful but it would have to offer me something compelling to make me switch over.