Don't forget to use a
local mirror of Debian repository -- some of them also serve in IPv6. There also exists a tool called netselect-apt that can be used to find the fastest repository.
As for basic binary repositories of my choice,
Code:
deb http://ftp.fi.debian.org/debian/ sid main non-free contrib
deb http://ftp.fi.debian.org/debian/ experimental main non-free contrib