grub2 - How to make grub stop appearing every time I boot?

I'm using Ubuntu 12.04 and grub selections appear each time I boot. This happens on both of my computers.

I have tried editing the /etc/defaults/grub to use default, to use the 0 entry, and ran the update on it. But nothing seems to solve the problem.

(showing uncommented lines)

$ sudo nano /etc/default/grub
GRUB_DEFAULT=0
GRUB_HIDDEN_TIMEOUT=0
GRUB_HIDDEN_TIMEOUT_QUIET=true
GRUB_TIMEOUT=10
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
GRUB_CMDLINE_LINUX=""
$ sudo update-grub
Generating grub.cfg ...
Found linux image: /boot/vmlinuz-3.2.0-25-generic-pae
Found initrd image: /boot/initrd.img-3.2.0-25-generic-pae
Found linux image: /boot/vmlinuz-3.2.0-24-generic-pae
Found initrd image: /boot/initrd.img-3.2.0-24-generic-pae
Found memtest86+ image: /boot/memtest86+.bin
  No volume groups found
done