benching is slightly over-rated. concentrate on dips. dips is as good of a mass builder to the chest as chinups is to the back. bench press is equal to lat pulldown on a machine. the body grows the best when its own weight is pushed against gravity, not the weight of another object. i'm not quite sure why, but i've seen it proven time after time.
also, 4 sets is way more effective than 3, although 5 sets is not much more effective than 4. 4 sets seems to be the magic number.
the most important thing is not number of sets, or reps in each set. its the weight multiplied by the Time Under Tension. whether you do 5 reps real slow, or 10 reps real fast....the time it takes you to complete that set is the most important. However, keep in mind that bodybuilders are not powerlifters. Don't train for strength, train for FEEL. a few sets of big weight for 3-5 reps is not going to build mass, especially when you jump off the bench and feel like beating your chest like a gorilla because you lifted so much. the most results come when you exhaust yourself not just for the last rep of the set, but for rep after rep after rep after rep.
try switching to sets of 20, instead of your usual 12,10,8 or 10,8,6 pyramid. do the same weight for 20 reps each set. if you need a spot on the last 10 reps of the last set, then do 20 reps anyway. this stresses the importance of negative reps for increasing your max load.
also, a variety of exercises is important. stick to the basic compound movements first and if you can do smaller movements later, then do so.
on a personal note....fuck barbell incline and cable crossovers. always seem to fuck with my shoulder joint or rotator cuff. i prefer dumbell incline and dumbell flyes but thats just me. also, on dumbell flyes if you can't almost touch the dumbells to the floor, you're using too high a weight. stop trying to impress people in the gym with the size of the weight in your hand and impress them later with your own size.
concentrate on each rep, dont just "try to get through it". focus on feeling that rep like you're trying to focus on performing brain surgery.