Some people are genetically gifted to have a "peak". Some just have a fat, thick, bicep that goes from shoulder to elbow. When flexed, it is round and big, maybe not with a peak on it though. What are your workouts like? It is possible that you aren't hitting them correctly or have bad form. Bad form usually accounts for a majority of people "not having a good bicep". No matter what exercise you do, keep it strict. Even with heavier weight. IF it gets sloppy and you start leaning and twisting to get a rep up, it's too much. Now there is something to be said for hitting a set of 10-12, with the first 8-10 being strict, and then the last 2 having to use a LITTLE body english to get it up. Just don't turn it into a back and shoulder exercise.