This Applescript take the selected file in Finder and open it with Sublime Text 2 (~/bin/subl). Using Alfred you can bind a global hotkey for this script, so you can edit your files with just a keypress, without worrying about the default editor.

Applescript to open selected file in finder with specific editor

tell application "Finder"
  activate
  set filePath to (POSIX path of (target of front window as alias))
  set fileAlias to the selection as alias
  set fileName to name of fileAlias
  do shell script "~/bin/subl " & filePath & fileName
end tell