yo tengo puestos los que vienen en la guia ubuntu ( www.guia-ubuntu.org ) que son estos :
## Uncomment the following two lines to fetch updated software from the network deb http://us.archive.ubuntu.com/ubuntu breezy main restricted deb-src http://us.archive.ubuntu.com/ubuntu breezy main restricted ## Uncomment the following two lines to fetch major bug fix updates produced ## after the final release of the distribution. deb http://us.archive.ubuntu.com/ubuntu breezy-updates main restricted deb-src http://us.archive.ubuntu.com/ubuntu breezy-updates main restricted ## Uncomment the following two lines to add software from the 'universe' ## repository. ## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu ## team, and may not be under a free licence. Please satisfy yourself as to ## your rights to use the software. Also, please note that software in ## universe WILL NOT receive any review or updates from the Ubuntu security ## team. deb http://us.archive.ubuntu.com/ubuntu breezy universe deb-src http://us.archive.ubuntu.com/ubuntu breezy universe deb http://security.ubuntu.com/ubuntu breezy-security main restricted deb-src http://security.ubuntu.com/ubuntu breezy-security main restricted deb http://security.ubuntu.com/ubuntu breezy-security universe deb-src http://security.ubuntu.com/ubuntu breezy-security universe deb http://archive.ubuntu.com/ubuntu breezy multiverse deb-src http://archive.ubuntu.com/ubuntu breezy multiverseEs una muy buena guia que te permite dejar la ubuntu bastante bien configurada y sin comerse mucho la cabeza 😉