What i do is this:
dumbell extensions/standing dumbell curls; 4 supersets of 8-10 reps
triceps pushdowns/incline dumbell curls; 4 supersets of 8-10 reps
lying tricep extensions/preacher curls; 4 supersets of 8-10
reverse wrist curls/wrist curls; 4 supersets of 15
.......if you want you can throw in some hammer curls and reverse curls instead of the wrist curls.......i usually do that. since you are using the supersets with those opposing exercises, it helps seperate the muscles, bringing out the defenition for toning. I added in the triceps exercises too, to get a full arm workout.