anything with a straight bar. e-z bars actually take stress off your biceps aswell so when going for mass BB is actually better. if you want a higher peak stick with close grip exercises. Close grib BB curls, incline Db curls also work great for the long head of the bicep. people think precher curls hit the long head and add peak but there actually mistaken it hits the short head much harder. however switch up to close grip preachers and youll build a higher peak. if your looking for fatness on you inner bicep stick with heavy shoulder width or wide grip curls these will add thickness to your arms. if you want detail do hammer curls, they hit your brachialis which is the muscle on the outside of your arm that ties in your triceps and biceps. if you want to hit this muscle even more do you hammer curls and bring he DB in front of your chest coming in from the side almost. you can do these heavy aswell to build this mucsle. hoped this helped. remember though, if you want bigger arms, hit your triceps they take up alot more space one your arms then your biceps do.
Do your biceps after your back routine and you're likely to see some immediate improvement. Recently I've been liking bent-over underhand barbell rows. It's pretty much barbell rows with and underhand grip, so you're going to more heavily involve the biceps. Quality, heavy back work with a few biceps exercises is all you need.
Ricky has a good post above me about various biceps-specific exercises. Personally, I'm fond of bar curls (barbell or curl bar), incline DB curls, lying DB curls (great stretch, good for your last biceps exercise) and preacher curls. I don't necessarily do all of those exercises, but those are my favorite. For incline DB curls, start with your palms facing each other at the bottom, then rotate the wrist on the way up and at the peak of the movement, have your wrist rotate so that your pinky is higher than your thumb, then give it a good flex before lowering slowly to a full stretch. Remember that the function of the biceps is to curl the arm but also to aid in wrist rotation. Rotate your wrists and you'll see your biceps contracting. That's why I think it's important to involve some wrist rotation during dumbbell work.
I usually do no more than 3-4 total sets for biceps after a back routine and sometimes I think that may be pushing it. You don't need 20 sets for biceps like some people think you do.