Casio FX-9860GII-L-IH Graphing Calculator
Casio shows us that TI and HP aren't the only games in town. The 9860's a great value and performs the same basic functions as the TI-84. It can perform many graphing functions and will be useful for undergrad math. It's accepted on the ACT, SAT, and AP Calc tests. It can also use USB. However, extra programs for it aren't as easy to find as for the other calculators. I like the looks of the other calculators better too. This calculator is worth it if you're on a budget, and it has spreadsheet support. Ultimately though, it's just not going to be as easy to follow along with the teacher when they're using a TI.