I'm using TextWrangler as my main editor and am looking for a macro command that can change the buffer I'm working on. It's really annoying having to touch the mouse each time I need to change file.
Look on the View menu for "Next Document" and "Previous Document". The default shortcut keys are ⌥⌘] (option-cmd-]) and ⌥⌘[ (option+command+[).
If the files are in different windows, use the standard OS X combination of ⌘+`