I've been playing with OpenBSD -current on my MacBook Pro.
Not all of the hardware works. Most notably: the ATI Radeon Mobility X1600, wireless, Fn key and acpi/apm.
I can get X working with the VESA driver at 1024x768.
So, I cannot right-click, recording through the azalia sound driver is not working (though deanna@ is making great strides with the Mac audio capabilities), none of the Fn-Fx keys (sound, brightness, ...) are working, I cannot suspend or get any power status. But, it's a fast, fast, fast build machine. :)