I gotta stand up a bit for decline here, because it's an essential part of developing your chest correctly. It's just as important as incline/close-grip as they work a different major muscle in your chest. More importanly, decline dumbells allow you to really contract your lower chest at the top of the lift and stimulate the muscle. I use it with dips during one of the two chest workouts I do every week and have seen results both in my strength (Flat Bench numbers) and appearance wise. Your lower chest is what gives your chest that bulky look, while the upper chest gives your chest a broad and wide look.
Just switch it in for all you who love to do dips every other week or something. But I strongly suggest you guys give it a shot, because it's working great for me