Dialogue and realism

I was perusing the webpage of a literary agent group recently, and one of the criteria they stressed for submissions was the use of natural and believable dialogue for the characters that would be age-appropriate. Now, I am not a fan of hyper-stylized "cool" banter you hear in movies and t.v. shows with teen characters these days; I think it's become a bit of a cliche to be honest. Nevertheless, I had a problem when preparing my first draft of "The Foster Children of Time." The first extended conversation was an exchange between Tony and some school buddies, and it was all "dude" talk, every sentence punctuated with "bro" and "homes" and the like. Reading it back to myself, it was absolutely mind-numbing. Around that time I had just watched a mid 60's era flick called "The Defilers." This movie featured the characters speaking in hip/beatnik 60's lingo (the kind you suspect real people never went in for much in real life) and in that aspect was fun and engaging (even if the movie was otherwise somewhat repulsive). So that inspired me to give the character "Carson" his particular voice -- perhaps a bit of a hybrid between Stan Lee banter updated with a touch of post-"Mean Girls" jive. It might not seem terribly realistic, but I think it's more distinctive -- and fun.