I kind of stick with basic, straight bar curls or db curls then I normally move onto incline db curls - this movement is great for stretching out the biceps and totally taking out any shoulder power then I adore standing bent over concentration curls - this gives me great peak.
Again I cant express enough of training with the right intensity, with biceps I fully warm them up and usually hit them with 2 working sets with a triple dropset - or 2 working sets with 2 forced and 2 negs, again these sets are to complete muscular failure and thats were many fall down not taking your muscle to complete failure and then push beyond.
Ive tried those seated BB curls but they never did much for me, but if your getting results stick with them but up the intensity by adding dropsets, forced, negs or rest pause, use which ever methods suit you at the time but just add intensity. And also
try those standing bent over concentration curls for the peak, stick with them for 3 months and when you bring the weight up try and bring your little finger slightly higher then your thumb and you will feel a sharp pain right in the peak/head of the biceps