Already had one of the smaller ones and now want something bigger and more exotic?
Remember, usually the bigger the bird, the bigger all of the considering factors apply - 
Happy child with a sweet Meyer's youngsterlike noise level, cage requirements, destructible chewing habits, "bite" definition, normal bird messiness. Sometimes bigger is not better; sometimes bigger is just "more." (Of course, if you already have a bigger bird, then you probably can skip this part).
You are doing the right thing by exploring all the birds you like.
I suggest that you pick out your intended species and join a Yahoo group associated with that species and get into the personal chats with owners of these birds. Please remember that all babies are sweet and precious and that, like teenagers, they may eventually grow teeth through those birdie-teens.
Listen to the people who have older birds. Of course, most of these will have graduated out of the "chat groups" as the newness has worn off, but there still might be an old soul out there that still feels the need to educate others about their "special companion."
No matter how conscientiously you try to pick the "perfect bird" for your personality and home situation , there will always be the "individual personality" of the bird you choose. As a parent, I can tell you that all the children do not fit the normal mode.
Sometimes it is all a crap-shoot, and you get what you get.
Some of the things you might take into consideration is your available time, on a daily basis:
Bigger birds are usually more complicated. They are masters of cause and effect.
They quickly learn your emotional keyboard and become skilled "pushers" to get their demands met.
Remember ... the more time they spend in the cage doing nothing ... the more time they have to plot their next manipulation of your life.
So for everybody's sake, give your bird a lot of supervised "free" time.