Oh! I had a TI-Nspire CAS (not the CX color model) and liked it very much! Sorry that I don't have experience with the Casio, but if I can tell you something:
Be VERY careful with the TI-Nspire CAS models! While it's a great calculator, the fact that it has a computer algebraic system (CAS) installed in it makes it ineligible for standardized testing, as well as most, if not all university classrooms. I don't know if anyone told you that prior (apologies, but I'm not reading every reply to know whether it has been stated) but it was explicitly mentioned in my college, and my college wasn't even a good college.
I can tell you for certain that as far as most "banned" calculators are concerned in academia, the TI-89, the TI-Nspire CAS (including CX version, obviously,) and one other calculator, I think it's an HP model, are most certainly restricted. Also, if it has a QWERTY keyboard, one of the standardized tests (ACT or SAT, forget which) will also ban it.
I'm just providing that from personal experience. The TI-Nspire CX or regular model is fine! You can use that without issue, as it doesn't have a CAS system nor a QWERTY keyboard, but the CAS is definitely a no-go, assuming your instructor is aware. They may not even care, but you should definitely check with them prior.