My .emacs file.

.emacs

(electric-indent-mode t)

(setq-default tab-width 4)
(setq-default indent-tabs-mode nil)
(setq indent-line-function 'insert-tab)
(setq tabify nil)
(setq-default c-basic-offset 4)
(delete-selection-mode 1)
(set-default-font "-apple-Bitstream_Vera_Sans_Mono-medium-normal-normal-*-*-*-*-*-m-0-iso10646-1")
(setq load-path (cons "~/.emacs.d/" load-path))
(add-to-list 'custom-theme-load-path "~/.emacs.d/themes/")

(setq whitespace-action '(auto-cleanup)) ;; automatically clean up bad whitespace
(setq whitespace-style '(trailing space-before-tab indentation empty space-after-tab)) ;; only show bad whitespace
;;; delete trailing whitespace
(add-hook 'before-save-hook 'delete-trailing-whitespace)

;;; turn on syntax highlighting
(global-font-lock-mode 1)

;;; xml-mode for gsp files.
(autoload 'xml-mode "psgml" "Major mode to edit XML files." t)
(setq auto-mode-alist
       (nconc
         '(("\\.gsp$" . xml-mode))
         auto-mode-alist))

;;; use groovy-mode when file ends in .groovy or has #!/bin/groovy at start
(autoload 'groovy-mode "groovy-mode" "Major mode for editing Groovy code." t)
(add-to-list 'auto-mode-alist '("\.groovy$" . groovy-mode))
(add-to-list 'interpreter-mode-alist '("groovy" . groovy-mode))

;;; make Groovy mode electric by default.
(add-hook 'groovy-mode-hook
          '(lambda ()
             (require 'groovy-electric)
             (groovy-electric-mode)))
(add-hook 'groovy-mode-hook
          (lambda ()
            (c-set-offset 'label 4)))

(setq linum-format "  %d")
(global-linum-mode 1)

(set-cursor-color "slategrey")
(global-set-key "\M-g" 'goto-line)

(setq frame-title-format
      (list (format "%s %%S: %%j " (system-name))
            '(buffer-file-name "%f" (dired-directory dired-directory "%b"))))

;; Auto-complete
(add-to-list 'load-path "~/.emacs.d/")
(require 'auto-complete-config)
(add-to-list 'ac-dictionary-directories "~/.emacs.d//ac-dict")
(ac-config-default)

(require 'ido)
(ido-mode t)

(setq path-to-ctags "/usr/local/bin/ctags") ;; <- your ctags path here
(defun create-tags (dir-name)
  "Create tags file."
  (interactive "DDirectory: ")
  (shell-command
   (format "%s -f %s/TAGS -e -R %s" path-to-ctags dir-name (directory-file-name dir-name)))
  )


;; Ruby flymake.
(require 'flymake)

;; I don't like the default colors :)
;;(set-face-background 'flymake-errline "red4")
;;(set-face-background 'flymake-warnline "dark slate blue")

;; Invoke ruby with '-c' to get syntax checking
(defun flymake-ruby-init ()
  (let* ((temp-file   (flymake-init-create-temp-buffer-copy
                       'flymake-create-temp-inplace))
   (local-file  (file-relative-name
                       temp-file
                       (file-name-directory buffer-file-name))))
    (list "ruby" (list "-c" local-file))))

(push '(".+\\.rb$" flymake-ruby-init) flymake-allowed-file-name-masks)
(push '("Berksfile$" flymake-ruby-init) flymake-allowed-file-name-masks)
(push '("Cheffile$" flymake-ruby-init) flymake-allowed-file-name-masks)
(push '("Gemfile$" flymake-ruby-init) flymake-allowed-file-name-masks)
(push '("Guardfile$" flymake-ruby-init) flymake-allowed-file-name-masks)
(push '("Rakefile$" flymake-ruby-init) flymake-allowed-file-name-masks)
(push '("Thorfile$" flymake-ruby-init) flymake-allowed-file-name-masks)
(push '("Vagrantfile$" flymake-ruby-init) flymake-allowed-file-name-masks)

(push '("^\\(.*\\):\\([0-9]+\\): \\(.*\\)$" 1 2 nil 3) flymake-err-line-patterns)

(add-to-list 'auto-mode-alist '("\\.rake$" . ruby-mode))
(add-to-list 'auto-mode-alist '("Rakefile$" . ruby-mode))
(add-to-list 'auto-mode-alist '("\\.gemspec$" . ruby-mode))
(add-to-list 'auto-mode-alist '("\\.ru$" . ruby-mode))
(add-to-list 'auto-mode-alist '("Gemfile$" . ruby-mode))
(add-to-list 'auto-mode-alist '("Guardfile$" . ruby-mode))
(add-to-list 'auto-mode-alist '("Guardfile$" . ruby-mode))
(add-to-list 'auto-mode-alist '("Guardfile$" . ruby-mode))
(add-to-list 'auto-mode-alist '("Guardfile$" . ruby-mode))

(add-hook 'ruby-mode-hook
          '(lambda ()

	     ;; Don't want flymake mode for ruby regions in rhtml files and also on read only files
	     (if (and (not (null buffer-file-name)) (file-writable-p buffer-file-name))
		 (flymake-mode))
	     ))

(custom-set-faces
 '(diff-added ((t (:foreground "forest green"))) 'now)
 '(diff-removed ((t (:foreground "firebrick"))) 'now)
 )

(if (window-system)
    (set-frame-size (selected-frame) 129 76))