TI-83 Plus

Released in 1999 as a successor to the TI-83, but not fully replacing it yet. Features more memory than it's counterpart, and backwards compatibility with 83 and 82 programs. Also provides a flash upgradable ROM.

[TI] [ticalc.org]

TI-86

Released in 1997 as a successor to the TI-85. Features an impressive 96k user memory, integrated assembly support, and an even more sleek case than the 83. Maintains backwards compatibility with TI-85 programs.

[TI] [ticalc.org]

TI-83

Released in 1996 as a successor to the TI-82, but to be replaced with the TI-83 plus. Had a sleeker case, more features. Notably, this was when Texas Instruments officially added assembly support. Backwards compatible with TI-82 programs.

A note on the case: The 83's that I've seen resemble the 86 depicted above, not so much what is shown here, but they're probably different versions.

[TI] [ticalc.org]

TI-82

Released in 1993, and generally replaced by the TI-83 / 83 Plus. The 82 was intended to be a more user-friendly version of the 85, meaning less features. It featured the same assembly-allowing loophole as the 85.

A note on the case: My 82 had a case much more similar to that of the 85, not what is pictured here. It was probably an older version than the one depicted here.

[TI] [ticalc.org]

TI-85

Released in 1992, and officially replaced by the TI-86. The 85 was the first graphing calculator with a link port, and the first with assembly programming capability (via a loophole).

[TI] [ticalc.org]