my 83+ serves me well, even in U.
My college lets people use TI-89s in most of the math classes. The only classes I think that dont let you use it are the remedial math classes, as they apparently havent learned how to do algebra in the first place. The only thing is, my math prof. pretty much will give you no credit if you dont show your work, so I use my TI-89 to check up on the work, as well as to graph.
P.S. does anyone know where there is a programming guide for the TI-89, i looked through the TI website but couldnt find it. Im planning on programming up an easier way to deal with vectors and matrices.