Are there different "flavors" of Mac OS X like there is of Windows? (Windows Vista Home, Vista Ultimate, Vista Business, etc.)

Are there different "flavors" of Mac OS X like there is of Windows? (Windows Vista Home, Vista Ultimate, Vista Business, etc.)

I've never really seen Mac OS X in different "flavors" like windows, does it have them? Or does Apple just give you one straight OS, as opposed to microsoft splitting up the OS into different tiers: