Biceps are your vanity muscles
In all seriousness, a good routine of chin ups (with varying grips) will improve overall muscle gains in your back and your biceps at the same time. Nothing wrong with adding a few isolation moves to add some extra pump to your bi's though. If you want big ARMS as a whole though, work your tri's. Do lots and lots of pushups with varying forms (i.e. regular, military style, diamond) and your tri's will be on fire. You can also add different isolation workouts for tri's, but I find after doing a bunch of sets of different pushups, I can do very little with my triceps because they are smoked.