C Programmer: Their '*' and ';' keys are worn out.
C++ Programmer: Their '>' and '<' keys are worn out.
Lisp Programmer: Their '(' and ')' keys are worn out.
OCaml Programmer: Their ';' key is worn out.
ALGOL Programmer: Their ':' and '=' keys are worn out.
Forth Programmer: Their ':' and ';' keys are worn out.
x86 ASM Programmer: Their '%' key is worn out.
Haskell Programmer: Their '-' and '>' keys are worn out.
Ruby Programmer: Their 'e', 'n' and 'd' keys are worn out.
Python Programmer: Their tab key is worn out.
SQL Programmer: Their 's', 'e', 'l', 'c', and 't' keys are worn out. (Actually, 'a','n','d')
Ada Programmer: Their 'i' and 's' keys are worn out.
Java Programmer: Their 'p', 'u', 'b', 'l', 'i', and 'c' keys are worn out.
Brainfuck Programmer: Their '>', '<' and '+' keys are worn out.
Perl Programmer: Their punctuation keys (all of them) are worn out. And the letter keys are crisp and clean.
COBOL Programmer: Their caps-lock key is worn out.
VHDL Programmer: Their '<' and '=' keys are worn out.
Fortran Programmer: Their shift keys and 'c' keys are worn out.
Fortran 95 Programmer: Their shift keys and '1' keys are worn out.
Erlang Programmer: Their '.', '-' and '>' keys are worn out.
G-code Programmer: No keys are worn, because there's a rubber keyboard protector (with metal shavings embedded in it).
There must be examples that cite the space, tab or enter keys, or? http://compsoc.dur.ac.uk/whitespace/?
XML Programmer: Their '>' and '<' keys are worn out.
sh Programmer: The "Ctrl" key is next to the 'a' key.
Newbie Programmer: Their F1 key is worn out.
APL Programmer: They have an APL keyboard.
PHP Programmer: The key mapped to '$' is worn out.
Documentation Editor (using Word): The 'e', 'Ctrl', and 'Alt' keys are worn out.
Experienced Documentation Editor (using Word): The 'Ctrl' and 's' keys are worn out.
Documentation Editor (using LaTeX): The '\' key is completely worn out.
Data-Entry Clerk: The entire numeric keypad is worn out.
Unlucky Programmer: The 'm', 'o', 'n', 's', 't', 'e', 'r', '.', and 'c' keys are worn out.
Slacking Programmer: The 'n' key is worn out.
Slacking, Opinionated Programmer: The 'n' key and the '!' key are worn out.
Slacking, Opinionated, Obnoxious Programmer: The 'n' key, the '!' key, and the caps-lock key are worn out.
GWBASIC programmer: The ? key and all the number keys are worn out.

objective-c programmer: his '[' and ']' keys are worn out.

english: they decide to read this thread and have no idea what is going on and think that the people who post to it should find a better way to spend their time

Bad typer: Delete key is worn out.

For PHP, I use ; far more often than $.

Red Alert 2 gamer that prefers the allies: their "d" key is worn out

[SCAR] Military Pilot: Their [Tab] key is worn out.

lebermac: his whole keyboard is fried from spilling a bit too much tequila on it