Cable Crossovers are a staple when the goal is to build an evenly developed chest. The use of cable resistance allows you a good pectoral contraction as you cross the cables over during the concentric phase of the motion. There is also good opportunity for a good outer pectoral stretch as you control the resistance weight during the eccentric phase of the motion.
The majority of cable machines allow you to set the cable at various angles. A higher angled crossover targets upper chest development while a lower angled cable targets lower chest development. A centered cable targets middle chest development.
Unlike free weights, cable crossovers give you the ability to quickly change the weight resistance, allowing for more effective drop set to fatigue the pectoral muscles.
Incline and Decline Chest Press are really good for maximizing upper body strength as well as hypertrophy (the enlargement of organs or tissues). Incline and Decline press allow you to target the upper and lower pectorals much like the cable crossover except it allows you to use heavier free weight to force stabilizer muscles to come into play. Incline and Decline chest press are standards in any chest development workout program.
With flat bench dumbbell presses, you lose resistance and therefore lose good inner pectoral contraction due to gravity. To alleviate this problem, try adding a lean to take advantage of gravity. Choose a sturdy rack or wall structure to grab with one arm extended and lean from a 45 degree angle. Then simply bring the dumbbell across your chest diagonally like you would during dumbbells fly. Keep in mind you will have to use considerably less weight than a traditional dumbbell fly but you will target and recruit more muscle fibers, which is the primary goal.