Emacs Brace and Bracket Highlighting?

If you're dealing with a language that supports it, give ParEdit a serious look. If you're not using with a Lisp dialect, it's not nearly as useful though.

For general brace/bracket/paren highlighting, look into highlight-parentheses mode (which color codes multiple levels of braces whenever point is inside them). You can also turn on show-paren-mode through customizations (that is M-x customize-variable show-paren-mode); that one strongly highlights the brace/bracket/paren matching one at point (if the one at point doesn't match anything, you get a different color).

my .emacs currently contains (among other things)

(require 'highlight-parentheses)

(define-globalized-minor-mode global-highlight-parentheses-mode highlight-parentheses-mode
  (lambda nil (highlight-parentheses-mode t)))

(global-highlight-parentheses-mode t)

as well as that show-paren-mode customization, which serves me well (of course, I also use paredit when lisping, but these are still marginally useful).

Apart from the answer straight from the manual or wiki, also have a look at autopair.