i'm awfully wary of photoshop adjustments, although i know it's stupid as camera adjusts images automatically anyways. i sometimes use brightness/contrast balance (not automatic) to make tine changes in very dark pictures. i use .jpg, not raw, because i'm lazy and also because i don't want to 'make up' the picture myself, i want it to be as close to reality as possible, and by postprocessing time i could forget how everything looked at the time of shooting.
i don't see how rotation can affect picture quality