In two areas I've wandered these years, mathematics has been extremely helpful: data mining and bioinformatics.

1. Yes and no. The math I learned in college was not that useful. If I'd gotten a minor in statistics and emphasized matrix math several jobs would have been much easier.

2. Some computer science programs are useful in the real world, others teach bad habits that need to be broken later. It depends. The best developer I've ever met hated computer science and dropped out of college.

3. I think the most abstract languages are easier in some ways, but that might depend on the individual.