Interesting post. Being as thought the OP is in my home state, I felt obliged to join the forums (have been a lurker for a while) in order to post some thoughts.
First, on the subject of Overdrive's age: I doubt that most of the comments regarding your age are specifically targeted at you necessarily because you are young. However, the tone and writing style certainly caused me to picture a younger pilot who was taking it upon himself to "save the world". Your age and number of flight hours do not necessarily dictate that you are immature, but please keep in mind that a TON of wisdom is gained from simply living life and observing the wide range of experiences out there. More specifically, you seem to believe that the offending pilot was operating dangerously and recklessly by flying 500-600ft AGL. You mentioned a lot of "what-ifs" about hitting a college tower, etc., which at your age (I'm not much older) I might have also been concerned about. However, after having been around more and more flying (less TT than you) I find that the activities aren't nearly as dangerous or risky as they originally appeared, and the probability of a fatal accident was still incredibly small. Flying 500' AGL isn't something I typically make a habit of, but I'm not about to contact the FAA because someone made a few low passes. If he was doing aerobatics or truly "buzzing" people, I'd be more inclined to agree, but it doesn't sound as though it was anywhere near that extreme.
Second, I do find your convictions to be in the right place, however your reluctance to talk to the gentleman flying the aircraft to be disheartening. You state (in a roundabout way) that it's our responsibility as airmen to report these possible breaches in FAA regs in the name of "safety". Obviously no one here would want to have it on their conscience if that pilot was later in an accident where he was killed or killed others, pax or on the ground. However, you are willing to go the distance to file the report, submit the video, and respond to additional FAA queries/possibly chastisement from fellow pilots . . . yet unable to simply pick up a telephone or send a letter/pic to the owner of the aircraft found in the registration database? If you efforts to curtail the situation verbally were rejected, and the pilot continues to make himself a nuisance, by all means go ahead and sic the dogs on him. If your neighbor doesn't know that his stereo is causing you annoyance, why not just talk to him instead of calling the police first? It's not about being a tattle-tale, it's more about trying to be civil to one another, especially to a member of a pretty elite membership like pilots are.
Finally, on the subject of choosing which regs to obey and which are bendable . . . it's not your job to make that delineation. I look at it similar to seeing someone on the highway speeding where there's a humorous saying, "Anyone driving slower than me is crazy, and anyone driving faster than me is insane!" My point being, it's often very difficult to draw the line at what should be reported and what shouldn't. I'm not calling the cops on some guy for driving 80mph in a 65mph zone just the same as I wouldn't report a guy for flying 300' under a cloud while flying VFR (assuming I could definitively prove he was doing so).
As was mentioned by several others, you're free to do whatever helps you sleep at night, but I'd recommend trying to help gain a friend through helpful discourse (the offending pilot) rather than surely making an enemy of him by calling the FAA. The downside to calling the FAA every time you see a reg busted is that you will have to do EVERY time you see one busted (or else your logic won't hold up) because no regs are ever to be busted without repercussion from the FAA. Another ugly caveat from that style of "enforcement" is that it can (and has) led to more and more FAR's time and time again. Legislating everything out of aviation would soon be so burdensome as to make the activity too unattractive for most.
The purpose of my post is not to call your age/flight time/knowledge/convictions into question, merely to present my outside viewpoint and hope that you'll keep an open mind in how you proceed with your actions.
It became what it is now because of other people becoming upset at me for reporting aircraft who should not be under FAR's over a city. 
the epitome of maturity. I've been pretty calm and mature with the whole thread considering all of the people throwing tantrums. At least in my opinion - which if this thread is any example, is always wrong according to the 'vast majority of pilots' who don't follow the rules and regs. 
