People at the gym always ask me what I do for arms, and the honest answer is 3-4 sets once a week of either hammer curls, barbell curls, or alternate dumbell curls. I stick them in at the end of the week mainly for injury prevention and I do them last in the week so that sore biceps can't screw up my pulls during the week. I just find it ironic that the curl jockeys at the gym ask me about biceps, when I really couldn't care less about them in terms of dedicating workouts to them.
I'm not quite 6' and weigh 250-255, arms are 19.5-20". Genetics probably play a role, but I can honestly say I don't isolate biceps anymore than I say I do.....right now I clean 3 times a week and row twice a week and I couldn't afford to do anymore than 3 or 4 sets of bis at the end of the training week......I am a big believer in getting strong at compound lifts in a legit rep range, and if you go into any commercial gym you'll see the guys with the smallest arms are the ones who pound away at every type of curl ever conceived every time you seem them and have no base of strength and don't do any squatting or pulling.
As far as your concern, who the hell cares?? Big arms are a nice bonus, but really mean nothing as long as the rest of your body is strong and powerful, everybody has their strong suits, just develop yourself the best you can through heavy cmpound lifts and get out of the mirror and you'll be just fine. A big neck, big traps, big shoulders, and big legs look a lot better than a Johnny Bravo-type of gym rat physique anyway.