I enjoy fish, but birds have a special place in my heart.
ALL cockatoos are hormonal and unpredictable. This includes Galahs, rosebreasted, etc. As a matter of fact, Galah's and Goffin's tend to be fairly nippy. Goffin's in particular are HUGE bundles of energy; keep this in mind. I would not recommend a cockatoo as a first parrot.
GCC (green cheek) tend to be quieter, but realize that all conures are fairly loud as well. This is a general rule. Sure, some may not be as vocal as others, but it happens. Sun conures are particularly known for being loud.
Another thing to consider. When you first get an animal, we are generally all about them and give them constant attention. A parrot will then expect this attention throughout it's life. When that attention cannot be given, say 2 or 3 years down the road, they will scream for attention. Sometimes they even pluck their feathers. This is how many of the problems arise. Just keep this in mind.
I must also highly encourage you to check out parrot rescues. There are thousands of birds in rescues across the world. They do not all have issues, and many were just given up because the newness wore off. Please see if there are any in your area. It is so rewarding to bring a rescue animal into your home.