If you just use Ubuntu or dual boot/multi boot Ubuntu with Debian, Mint, Arch, Fedora, openSUSE, Windows, etc. this will give you all the information to create a custom background, fonts colors and menu that never needs modified.
You can also choose the default OS and the timeout before the default OS is selected. That will never need changing even when a new kernel is installed in any Linux system.
It has been updated for UEFI/GPT partitioned systems.
The only time you would need to modify anything is if you get bored with the background picture, font colors or if you install/remove/re-install an operating system.
The Wiki evolved from this thread: How to: Create a Customized GRUB2 Screen that is Maintenance Free.
There are several examples of what your screen could look like.
There is a link in the bottom of the Wiki that links back to this thread to post questions, comments, problems, etc.
All Linux systems are pretty much the same as far as customizing grub goes but, Arch is a little different see here for Arch Linux.
Grub has gotten much simpler and you should find that it is easier to customize. The Wiki has been updated with the ability to boot into the backup kernel.
If you choose not to have that ability, just omit that part and go with 2 entries per system instead of the three in the Wiki.