After hours of searching, compiling avahi-daemon myself, crying and sleepless nights it turns out if you are running Mac OS on non-apple hardware, and you have a mainboard with a Realtek r1000 series card (i.e. my ga-ep45-ds4) you should definitely use the RealtekR1000 driver if you want bonjour!
Although the hardware is detected by default, somehting isn’t supported and causes the broadcasts from avahi and Mac OS to be dropped. You will need XCode to build the sources, or look for pre-compiled ones on the net. More on my hackintosh later.