You have asked a great question; the answer as you see is more complex. THere are so many breeds of chickens that there is one for every situation.
Are you free ranging? Woods? Fields? mowed lawns? Or will they be confined most of the time? OR some of the time?
What preditors are a problem? Hawks? Coyote? Domestic dogs?
Are you breeding to increase the numbers or buying replacements? Do you need a broody hen or will you use an incubator?
For Eggs? FOr meat? for both?
My boys are 7 and 9, and they are on guard when the roosters are free ranging. THe black sexlink roosters have flogged the boys. THe boys play with the Lt sussex hen, the buff orpington and the speckled sussex. THe SS are underfoot when I'm weeding looking for a treat! LOL I will be adding buckeye as I have heard of the gentle temperament of the roosters, the very good meat and moderate egg production.
I bought a few of many kinds of breeds to see which would work for me and my family; then I figured I could focus on the breeds that worked best for us.
THe co-op will be good in that you will be able to ask all the important questions about temperament. We have one EE that is a real peach. So I bought 10 more from another source. Only 1 was a sweetie like my first one.
Live and learn. Read all the breed threads too.
GL