My biceps are my best muscle; this is what I do;
whenever doing back I make sure to make my arms participate as much as they can in the movement. You always hear not to do this, but I say that is bs. If you think about it, you always use as much tris as you can when benchin, your chest still gets big, so why not do the same with compound pulling movements!? TO do otherwise just creates inbalance and disproportion, the tris get super thick from compound pushing movements and the bis get left out, no amount of heavy lifts can make truly equal the difference. Anywas, using pullups as an opportunity to let your back assist your bis in heavy contraction does wonders for bicep thickness and mass.
Here is my arm routine (I alternate bicep/brachials with triceps excercises):
preacher curls, 3 sets, 8 reps
hammer curls, 3 sets, 8-12 reps
straight arm standing dumbell curls, 3 sets 8-12 reps
heavy cheat curls for 3 sets of 4-8 reps *
* do cheat curls at start or finish of workout (if done at finish you use less weight of course). Cheat curls are the best!
also reverse curls instead of hammer curls everyother workout is good. If you are strong enough you can do both each time, once you get the mass, superset the hammers with the straight arm dumbell curls for best results.