<p>I agree with the Mathematica comment. Or at least Maple. If you’re into programming, learn Matlab.</p>
<p>My math professor last semester (who taught multivariable calculus for engineers) told us he’s never owned a calculator in his life: calculators are antithetical to math. Then again, he’s a pure mathematician. If you take physics or chemistry classes, calculators will be valuable, but pretty much only the scientific functions. A Ti-84 will give you more than you’ll ever need, or else you’ll be using a computer to do actual computations.</p>