[sciguy125]

It's been awhile since I've taken those standardized tests, but I don't recall ever needing my calculator for anything other than arithmatic and trig. Any $15 scientific calculator probably would have sufficed.

As for calculators in general, I like the TI-86. While the 89 has more advanced calculus functions, the 86 seems to be more geared toward engineering in terms of layout and little functions here and there. Of course, having an 89 won't help you in calc if your teacher doesn't let you use calculators on the test (as was the case with 3 of my 5 classes). And in my engineering classes, I seem to be more productive with the 86 than my classmates with 89s. I don't know if they let you use the 86 on the ACT, so that may or may not help you.