I am a massive McDonald's junkie, I've actually had it every day for the past three days now. Nothing compared to some people I know, but it is still such bad nutrition! I need to get back into the habit of salads, those green balls of delight.
I tend stay away from junk food as often as possible as I am trying to remain lean & muscular. I should also add that if you can fit crap into your macros you aren't doing yourself a great deal of harm - I've seen fit, lean and muscular guys eat pizzas and chips, etc. I personally try to have cheat meals only once or twice per week or in instances which I am unable to prepare anything healthier.
I eat junk food a fair bit, only becuase I hardly gain fat from eating food and I've gotta keep up the calories for dem gainz. By junk food I mean takeaways, pasties and stuff; I try to avoid snacking and rather get as many solid meals in as I can, which is where stuff like Chinese takeaway comes in handy because you're always hungry again an hour later