My default .emacs has the following hooks for tex-mode:

  (add-hook 'TeX-mode-hook 'turn-on-auto-fill)
  (add-hook 'TeX-mode-hook 'ispell-minor-mode)
  (add-hook 'TeX-mode-hook '(lambda () (setq tab-width 8)))
  (add-hook 'LaTeX-mode-hook '(lambda () (latex-math-mode)))

Funny things happen when editing LaTeX source, however. For
example, typing the sequence (when editing a latex file)

"{\address 503 dgfd dfgdfg  \\
        sdfsf 1V9"

(just typing everything within the quotes, not the quotes
themselves, including the newline, and the indent is
produced by a tab). The cursor should now be directly after
the number nine. Press space. Instead of advancing the
cursor and inserting a space, the cursor backs up to before
the 9 and then inserts a space.

VERY annoying when typing. In fact, for certain key
combinations, there is no way to stop it. Sometimes to
append text to a line you have to begin typing on the next
line, and then join the lines by using "backspace"!

Funny - I wrote a 150 page thesis using this same latex mode
under RHL42 and the emacs stuff worked flawlessly...