I work in the audio industry where I route audio over ethernet and also use USB devices in development to flash devices (like putting firmware on USB stick and

I work in the audio industry where I route audio over ethernet and also use USB devices in development to flash devices (like putting firmware on USB stick and then taking said USB device to the audio hardware). I also use my FireWire for running external mic preamps; it's really useful to have a rack mounted 8 channel mic preamp on FireWire and to turn up and record a practice / gig with just your laptop, particularly as the ADCs in the external hardware will be significantly better than the ones in the MacBook. I use the ThunderBolt / Mini DisplayPort for hooking up to an external screen when I take the laptop home and want to game in Windows after rebooting; it is useful to have a device that will do all of that without external hardware, and I don't feel the extra pain of having a laptop half a centimetre thicker than a Retina model :-) And the SD? For my ancient camera! And the DVD writer is useful for giving CDs to other band members who don't like MP3s for odd reasons, or to play CDs in the car (yes my "ancient" 2008 Golf TDi supports MP3 CDs but the iPod interface for it is severely inadequate). You're right about the Pro though - it's probably the thing I'd buy again.