My view on the nerd/jock stereotype thing? In my high school, there were certain...not all, but quite a few...football (American football) players who apparently got so much hero worship for playing sports they decided they were better than everyone else and the only way they could maintain that feeling of supremacy was by picking on the "nerds." Or "geeks." Or "dorks," "poindexters," or whatever other tags they felt like heaping on people who they knew (or thought) wouldn't fight back.
See, because of their "status" as football players, they figured they didn't need to work in any of their classes - they'd just coast by and the teachers would give them passing grades for doing nothing - and therefore to them, anyone who actually demonstrated an interest in doing well in intellectual classes was obviously someone they could (and, in fact, SHOULD, in order to appear more macho in front of their fellows) make fun of.
I was on the "nerd" side of things - insulted verbally, pushed around, tripped in the hallway, locker broken into and one of them took a shit in it - that sort of thing. And I just dealt with it quietly, trying my best to ignore them...at least until one particularly abusive dick decided to start pushing me around in the middle of the hallway without a whole bunch of his friends around to back him up...and I proceeded to completely snap, grab him by the throat, and ram his head into the wall about a half-dozen times - I think he was unconscious by the second, but I was too pissed off to stop until about four other students literally dragged me off the sonofabitch.
Nobody EVER picked on me again after that.
Nowadays, I don't pre-judge anyone based on their size, whether they have a gym membership, whether they play sports, whether they drink, or whatever. Some people who do all of those things are good friends of mine. It's when that sort of person - or, for that matter, any sort of other person regardless of their size - decides to treat someone else like shit because they think they're better than that someone else that I get angry. Or to put it more succinctly, it's not what you are, it's how you treat others.