Working with grub used to be somewhat of a pain. The biggest complaint being that if you, say, disabled apic using the noapic boot option, and updated the kernel without updating the grub file, you could be stuck with a kernel panic. This was happening to me tonight when working with jeos and VirtualBox.
Automagic has made this a whole lot easier. There are automagic options in /boot/grub/menu.lst that are used when any kernel is installed into the system.