cn99的源是国内最快的，下面列出的就是Ubuntu 7.10(gutsy)的源：

对于电信网络用户，推荐希网的源，速度非常快。

deb http://ubuntu.cn99.com/ubuntu gutsy main restricted universe multiverse
deb-src http://ubuntu.cn99.com/ubuntu gutsy main restricted universe multiverse
deb http://ubuntu.cn99.com/ubuntu gutsy-backports main restricted universe multiverse
deb-src http://ubuntu.cn99.com/ubuntu gutsy-backports main restricted universe multiverse
deb http://ubuntu.cn99.com/ubuntu gutsy-proposed main restricted universe multiverse
deb-src http://ubuntu.cn99.com/ubuntu gutsy-proposed main restricted universe multiverse
deb http://ubuntu.cn99.com/ubuntu gutsy-security main restricted universe multiverse
deb-src http://ubuntu.cn99.com/ubuntu gutsy-security main restricted universe multiverse
deb http://ubuntu.cn99.com/ubuntu gutsy-updates main restricted universe multiverse
deb-src http://ubuntu.cn99.com/ubuntu gutsy-updates main restricted universe multiverse

此外还有 Ubuntu 中国官方源，服务器位于上海，也是电信网络。

deb http://cn.archive.ubuntu.com/ubuntu gutsy main restricted universe multiverse
deb-src http://cn.archive.ubuntu.com/ubuntu gutsy main restricted universe multiverse
deb http://cn.archive.ubuntu.com/ubuntu gutsy-backports main restricted universe multiverse
deb-src http://cn.archive.ubuntu.com/ubuntu gutsy-backports main restricted universe multiverse
deb http://cn.archive.ubuntu.com/ubuntu gutsy-proposed main restricted universe multiverse
deb-src http://cn.archive.ubuntu.com/ubuntu gutsy-proposed main restricted universe multiverse
deb http://cn.archive.ubuntu.com/ubuntu gutsy-security main restricted universe multiverse
deb-src http://cn.archive.ubuntu.com/ubuntu gutsy-security main restricted universe multiverse
deb http://cn.archive.ubuntu.com/ubuntu gutsy-updates main restricted universe multiverse
deb-src http://cn.archive.ubuntu.com/ubuntu gutsy-updates main restricted universe multiverse
对于网通网络用户，可以考虑使用台湾的源。
Ubuntu 台湾官方源（服务器实际上也是位于台湾大学的）：

deb http://tw.archive.ubuntu.com/ubuntu gutsy main restricted universe multiverse
deb-src http://tw.archive.ubuntu.com/ubuntu gutsy main restricted universe multiverse
deb http://tw.archive.ubuntu.com/ubuntu gutsy-backports main restricted universe multiverse
deb-src http://tw.archive.ubuntu.com/ubuntu gutsy-backports main restricted universe multiverse
deb http://tw.archive.ubuntu.com/ubuntu gutsy-proposed main restricted universe multiverse
deb-src http://tw.archive.ubuntu.com/ubuntu gutsy-proposed main restricted universe multiverse
deb http://tw.archive.ubuntu.com/ubuntu gutsy-security main restricted universe multiverse
deb-src http://tw.archive.ubuntu.com/ubuntu gutsy-security main restricted universe multiverse
deb http://tw.archive.ubuntu.com/ubuntu gutsy-updates main restricted universe multiverse
deb-src http://tw.archive.ubuntu.com/ubuntu gutsy-updates main restricted universe multiverse

台湾大学源：

deb http://ubuntu.csie.ntu.edu.tw/ubuntu/ gutsy main restricted universe multiverse
deb-src http://ubuntu.csie.ntu.edu.tw/ubuntu/ gutsy main restricted universe multiverse
deb http://ubuntu.csie.ntu.edu.tw/ubuntu/ gutsy-updates main restricted universe multiverse
deb-src http://ubuntu.csie.ntu.edu.tw/ubuntu/ gutsy-updates main restricted universe multiverse
deb http://ubuntu.csie.ntu.edu.tw/ubuntu/ gutsy-backports main restricted universe multiverse
deb-src http://ubuntu.csie.ntu.edu.tw/ubuntu/ gutsy-backports main restricted universe multiverse
deb http://ubuntu.csie.ntu.edu.tw/ubuntu/ gutsy-security main restricted universe multiverse
deb-src http://ubuntu.csie.ntu.edu.tw/ubuntu/ gutsy-security main restricted universe multiverse
deb http://ubuntu.csie.ntu.edu.tw/ubuntu gutsy-proposed main restricted universe multiverse
deb-src http://ubuntu.csie.ntu.edu.tw/ubuntu gutsy-proposed main restricted universe multiverse

另外，ubuntu-cn 的配置对于中国用户来说也是不可少的，可以采用 cn99的设置：

deb http://ubuntu.cn99.com/ubuntu-cn/ gutsy main restricted universe multiverse

针对不同的版本，只要修改gutsy 为你的版本号即可。