Overall, I'd take a TI 84+ SE. Monochrome, reliable, the cable is readily available, 15mhz cpu, and lotsa flash memory! I'm also most familiar with it that line in general.
I'd pick the 83+ SE if it was a "desert island" deal, where the (personally deal-breaking) proprietary cable isn't an issue That clear case is great, as said above.
My only other aside: if possible, id try to jerryrig a rechargable battery to either one. Just a quality-of-life thing, and the only thing that has me considering an 84+ CE seriously.

I would definitely go for the Casio fx-CG50 / Graph 90+E which is really a nice calculator to program.
It is clearly not as powerful as HP Prime or TI nSpire but it can handle quite interesting addins (utilities and games).
With a more powerful CPU and more RAM/Flash, that would be the absolute perfect machine.

I like the 84+ SE but I absolutely hate the original 84+ form factor. A monochrome screen is definitely required, as I'd likely be playing games on it half the time anyways, and if it's got high res color graphics like a casio Prizm then I may as well play a mobile game. Besides, casio has a much smaller community, and the prizm is built like shit compared to the 84+CE. (though strictly for math purposes, the hardware specs blow TI out of the water and so a prizm is my everyday carry model)

In the end, I think the retro charm of the monochrome calcs edge out any of the color screen competition, 84+CE included. Additionally, the weirdly shaped buttons of the original TI 84 series (84+/C/SE) automatically disqualify it, better LCD contrast and computing specs be damned. Leaving me with.... the TI-83+ SE.
Which, I don't have. I'll just make due with my original 83+ for now.

This is a tough question.

For me, the single calculator would have the most features.

I'm leaning towards the TI-Nspire CX II CAS (which I should use more often):

* The Nspire allows me to document programs and notes.
* I sometimes (and should more often) work with computer algebra.
* I want to have the most functions that available to me.
* For quick calculations, I can use the scratch pad.
* The Nspire also has finance functions.

For me, I love the TI-68k calcs. They have all the features that I ever need, plus I'm most familiar with them, both for using and for programming.

Between the 68k calcs, I would pick my TI-92 Plus over a TI-89(T), as I love the form factor and I use one as an everyday carry, despite missing a few features from the TI-89 Titanium. I've never used one, but the Voyage 200 combines the newer OS of the 89T with the form factor of a 92, so I'd probably pick that if I had the chance to evaluate its ergonomics first.

I've just never gotten into using my nspires, even though they are objectively more capable and powerful than the 68k calcs, and I find the (e)Z80 calcs to be too limiting in terms of features.

Disclaimer: I (currently) only own and have experience with TI calculators.

Definitely the Nspire CX CAS. I've carried one in my pocket everywhere I go for the last ~10 years. I have fond memories from high school and college hacking it to run various games and emulators, and even Linux. From a practicality standpoint the Nspire also does everything I could possibly want a calculator to do.

TI-84+CE, It has basic functionality, can run assembly, and C, it is also all the rage in the comunity these days, and has Celtic CE and CEaShell, you can downgrade it or jail break it, overall a solid model. Other wise, I'm choosing the TI-nspire CX 2, becuase once TI stops supporting it, it will become an infested play ground for games due to how it has much better graphics and also a touch pad.

TI-84+CE, It has basic functionality, can run assembly, and C, it is also all the rage in the comunity these days, and has Celtic CE and CEaShell, you can downgrade it or jail break it, overall a solid model. Other wise, I'm choosing the TI-nspire CX 2, becuase once TI stops supporting it, it will become an infested play ground for games due to how it has much better graphics and also a touch pad.

Anyone who says anything other than the TI-84+CE non-python revision m is wrong.

What about the TI-84 Plus CE revision pre-M? You am able to run BOS on them, as well as [REDACTED]. I know CEmu exists, but it felt cool to put BOS on my rev I.

If you ignore Python, the 84+CE Python is not too bad. Both of my sisters have CE Python calcs for school. At the end of the day, most students basically use it a a magic math box that plots functions.

Your right, it is kinda limited, but it has a wide range for Basic, Asm, and C

Well, I go with my gool ol' TI-84 Plus CE. It is the first (and only) one I have, and it does most things I need it to.