I always walk or take public transit. My partner and I share a car and he usually has it since he works full time across state borders.

I prefer to walk, however, if I want to go anywhere it is a >30 minute walk to the closest stores.

I walk if I can. Why not? It's good for you, but time and weather are also a factor.

Well, I would rather take a car because I live in a crummy neighborhood but I don't have a car sadly.

I usually drive because there aren't any stores near me.

That depends on what the errand is and how far the place I need to go to is...we live in a small town but even the nearest convenience store is nearly a mile away.
If I were just running out to mail something or pick up a few (fairly lightweight) items then I'd probably take my bike, but for things like grocery shopping and doctor's appointments we usually take the van.

Since the nearest gas station/convenience store is 8 miles from home--the car. Town is 14 miles from home--we have no choice but to drive.

I would much rather walk but that's impossible around here. I'd be willing to say that 85% of our streets don't have sidewalks, we aren't close to any public transportation, and our cab companies are incredibly unreliable. If we lived downtown, it would be slightly better but it'd still be a hassle.