I always try to get a spot on the end of an aisle, preferably next to an island. If I am at work, I will park next to people I work with who will be there all day long just like me. I also avoid parking next to trucks and SUVs, especially ones from the 70's and 80's. I also try to park away from the front row spaces, where cars are constantly leaving and entering. However, I don't park so far away that my car becomes a target to punks and theives.
Taking up more than one parking space is just asking for trouble. I've seen people deliberately push shopping carts into cars taking up more than one space. I've also seen it go as far as having a pickup truck tie a rope to a car, and drag it into one parking space. This guy tied a rope through the spokes on a rim and just pulled the car right over. Then he parked right next to it. Not to mention taking up two spaces draws unnecessary attention to your car and it will wind up getting broken into or keyed.