When I was taking courses in calculus and physics, I used the TI-86 because it had more functions and was more powerful, for the kind of math that was needed.
However, the TI30XIIS is an excellent scientific calculator. It has most of the functions of a scientific calculator, with the scrollable screen that lets you check your numbers before multiplying, and perform many operations using the "Ans" function. As an organic chemist, it's the only calculator I need when it comes to doing simple chemistry calculations, which involve a lot of basic operations.
If you need to do derivates, integrals, polynomials, etc, then you should get something more powerful. If you just want a calculator to do your basic math yet allow you to check your numbers with ease, then this is a great calculator to have.