I think it depends on your location. Are in you in the middle of the city or in a more rural area - do you have predators where you live?
You live in Florida, right? We are in AZ and definitely did not want a 'real' coop because if would have been way too hot for our chickens during the summer. We built a 3 sided coop/shelter and attached it to a covered dog run (you can see it on my BYC page). My mom used to live in Young, AZ (where they occasionally get snow,) and still didn't have a 4 sided, enclosed coop. She had a shelter for them that protected the chickens from rain, snow, & wind - the cold didn't seem to bother them.
There are several people I know here in my town that don't even have a coop or run (most yards here are enclosed by tall fences). Their chickens free-range safely and sleep in trees (but these chicken owners live in the middle of the city with no chicken predators around). I have mine in an enclosed run because we have a dry wash behind us that does have wildlife in it.
I'm not saying you don't need a coop, but you might want to check with other chicken owners in your area and see what's been working for them. Your climate & wildlife situation makes a big difference as to what you can get away with or even what would work best for you.