I'd agree with it being a judgement call, but my preference is to back in. At home, I have underground parking. Big pillars everywhere, including one right next to my spot. I always back in, so that I have a clear view when pulling out in the morning.
In a public parking lot, if two spots are aligned, I will pull through. I never have enough groceries or other stuff to need my trunk, anyway. If no two spots are aligned, I will go in nose first, especially if there are a billion people and carts floating around.