For regular workouts, I usually supplement my Preacher curls, with Spider curl, on the other side of the preacher bench.This allows for more extension and isolation. For getting ripped arms, I concur with what is already posted, 21's are excellent.
For back muscles, if you aren't seeing any difference, most likely you aren't going heavy enough. Remedy this by using 150 percent the weight on your deadlifts, but only lower them to your knees. This will Target and Isolate the Rhomboids. Also vary your exercises.
For triceps, do not underestimate the power of supplementing simple heavyweight pushdowns with decline closegrip bench presses in the smith rack. If you don't have a horsshoe, do these two along with rope pushdowns and you'll have them within weeks. That's a guarantee !
For abdominals I recomend doing decline leg raises, starting with a fully stretched body then curling the legs, finally finishing up with your knees at your chest, so your ass leaves the bench. If that doesn't get the burn going nothing will.
For shoulders, just correct form and wide grips will aid the deltoid growth, and more weight will make the traps grow.
One last trick for biceps : Drag Curls for the outside biceps. I trust you know what they are. Just do a knuckle grip on the bar, keep your elows close by your side (like a reverse curl) and your shoulders low. Now move the barbell by alongside your body, as if dragging it.