I don't use Kies, but I needed the drivers so my PC would recognize my phone. I just drag and drop files from my PC to my phone and back. Your Mac needs drivers to recognize your phone. You can get the correct drivers from samsung.com - click on support. Just search for your model and hit download and it'll show you the drivers for your Mac. <edit> You shouldn't have to install Kies to connect to your MAC but, given that you're not seeing USB in your notification bar, I thought installing the correct Kies might help. Unfortunately, you'll need Kies at some future point anyway, so might as well get it overwith
This is how it should work:
-Enable usb debugging from Menu > Settings > Applications
-return to home screen
-plug usb cable in
-pull down status bar
-press ‘ connect usb storage’ button (At this point, since you don't see anything in your notification area, if you go into settings>wireless and network> USB Utilities, what happens if you press the button "Connect the storage to PC"