Let me know if you want to chat in IRC. I'm trying this from a USB drive created from dd if I remember correctly.
When I choose the "Fedora Media" option, it then goes to "Welcome to GRUB, Then Grub menu (2.00) with "Fedora-18-x86_64-Live-Desktop.is" and "Verify and Boot Fedora-18-x86_64-Live-Desktop.is" options. I choose the first and then it said Booting 'Fedora-18-x86_64-Live-Desktop.is'. I see a steady cursor, and then after that, I just get a black screen.
I rebooted and tried verify instead, and it did the same thing.
Re: Macbook 4,1
When I choose the "Fedora Media" option, it then goes to "Welcome to GRUB,
Then Grub menu (2.00) with "Fedora-18-x86_64-Live-Desktop.is" and "Verify and Boot Fedora-18-x86_64-Live-Desktop.is" options. I choose the first and then it said Booting 'Fedora-18-x86_64-Live-Desktop.is'. I see a steady cursor, and then after that, I just get a black screen.
I rebooted and tried verify instead, and it did the same thing.