I am dual-booting Lucid and Snow Leopard on a Macbook Pro 5,3. I have uninstalled rEFIt, and I am wondering if there is a way (without reinstalling rEFIt) to boot automatically to the GRUB menu without requiring me to hold Option and select the "Windows" partition at each boot. Since there is actually no Windows installation on my computer, I can't access the Boot Camp Assistant to tell OS X to boot to the Windows partition by default.
In OS X there is the Startup Drive section in System Preferences. Ideally you should be able to select Ubuntu as the default drive there. I wasn't able to, I just set refit to only show up for one second in the config file (not difficult to do). I only see refit for a split second so it doesn't really bother me.
Also if you only want to use GRUB, I'm assuming you still want access to OS X. Without chainloading GRUB you can't boot directly into OS X from the grub menu. The option is there but it won't work properly, so that's another reason to see refit for a second at bootup.
Hold down option while booting, but when the drives appear hold down the left control key before you click on the Windows drive. That will change the appearance of the icon beneath the drive to a circular arrow, and if you click on that it should set that as the default selection for future boots without holding down option. I'm not sure if that will help, but that is how it works on my Macbook Pro 5,2 dual booting OSX and Grub/Linux.