<p>Complex analysis? Useful for grad-level physics and some kinds of engineering, I know that.
Vector analysis? You probably covered half of it in multivariable calc anyway, and it’s also useful for physics and some kinds of engineering.
Probability and statistics? Everybody should take a class on this. I wish I had time to take a proper probability and stats course.
NUMERICAL ANALYSIS!!! Too bad it’s in a fake language, but it should still be useful.
Chaos and dynamical systems, woot! I wish I had time to get a double major in math.
Transformations and geometries, sounds like it could be useful for computer graphics.
Ah, differential geometry. Necessary for general relativity.</p>
<p>Numerical analysis should be the least-rigourous and the least proofy. If you are comfortable with programming it should be a cinch!</p>