Where are most of the offices in Adelaide?

Hi, I was wondering if there is CBD like Sydney / Melbourne in Adelaide too or are the offices spread all over the city? I need to know this to figure out where to live in Adelaide. I lived in New York City and Downtown NY is the corporate hub and it was convenient living in Manhattan and travelling downtown for interviews etc. in the first few weeks at least. But when I moved to Florida, the offices are spread all across - thankfully I had a car and could drive around but this is not a privilege I would have in SA to start with. Still I had to break my leases and ended up losing some money to move closer to my work place and save time in travelling. I am concerned more about Banking and Financial institutions and Insurance Companies. Cheers!