Given that you're already familiar with the TI-83, I suggest considering the TI-89 Titanium. In language and UI design it's a descendant, but it is “modernized” in a lot of ways and has many additional features.
Easy way to convert between hex, dec and bin bases, with a few button presses rather by than executing a custom program.
You can enter numbers like
0b1011, and print them with the
▸Dec operators, or set the default output format to any of the three bases.
Support for integers with different word sizes: byte, word, double word etc (8, 16, 32 bit).
Only 32-bit is available; you'd have to do bit masking yourself to simulate smaller sizes.
Support for bit shift, OR, AND, NOT and similar binary arithmetic.
shift(value, count) provides a 32-bit sign-extending shift.
not act bitwise on integers.
The ability to type out the whole calculation/equation on the display as done on Texas calculators. Not "one operand at a time" as in more classic/simplistic calculators.
Yep, it's a TI! Also, if I remember correctly, the TI-83 text entry defaults to overwrite mode — the TI-89 defaults to insert mode like modern text editors.
Trigonometry supported and easily accessible (like on the Texas ones). Radians + degrees.
Yes. Trig functions are on the main keyboard, radians and degrees are available as a mode setting, and you can also enter and read vectors in polar or rectangular form.
Must support engineering notation.
Yes. The TI-89 has a dedicated key for entering the exponent "E" (which is a distinct character from text/variable-name "E". There is also an "engineering" output option to always use exponents that are multiples of 3.
Some manner of graphic display (LCD, TFT etc). Resolution doesn't matter.
160 × 100 LCD, no backlight. You can plot functions and also draw arbitrary graphics from programs. The normal input/output view fits 5½ lines of text (at minimum height; divisions and matrices and such are taller), and you can scroll up easily to review and recall previous results.
Actual buttons. (If I liked typing on touch screens, I'd use the app on my phone instead.)
Features/differences you didn't ask for but are noteworthy compared to the TI-83:
- You can have arbitrary, multi-character variable names.
- You can perform symbolic operations, including solving, factoring, expansion, differentiation, and integration.
- Instead of built-in function names being special symbols, you can just type their name on the keyboard. (There's still a list you can review and pick from, and a help function showing the expected parameter list.)
Tip: First thing to do is to go into the settings and turn off "Apps Desktop", so you always start at the "Home" regular calculator input mode.
The TI-89 Titanium is still in current production and can also be found cheaply on the used market (presumably from ex-students).
I hear that the TI-92 / Voyage 200 has the same operating system but adds a QWERTY keyboard, which may be of interest for quickly typing operator names. However, there is no model of this line in current production, and I am not familiar with the functionality of the newer TI-Nspire line.