There's a slightly outdated list at: http://ubuntuforums.org/showthread.php?t=185758

DropBox

Repository for DropBox.

deb http://linux.getdropbox.com/ubuntu intrepid main #Dropbox
deb-src http://linux.getdropbox.com/ubuntu intrepid main #Dropbox

feisty-commercial

## feisty-commercial by canonical
## currently has realplay (realplayer 10) and opera (opera 9)
## only uncomment it if you need it
deb http://archive.canonical.com/ubuntu feisty-commercial main #feisty-commercial

Google

deb http://dl.google.com/linux/deb/ stable non-free #Google software repository

LaunchPad Projects

Aguignard (Sonata, a MPD client)

deb http://ppa.launchpad.net/aguignard/ppa/ubuntu intrepid main #Sonata
deb-src http://ppa.launchpad.net/aguignard/ppa/ubuntu intrepid main #Sonata

Bazaar

deb http://ppa.launchpad.net/bzr/ubuntu intrepid main #Bazaar
deb-src http://ppa.launchpad.net/bzr/ubuntu intrepid main #Bazaar

Bazaar BETA

deb http://ppa.launchpad.net/bzr-beta-ppa/ubuntu intrepid main #Bazaar BETA
deb-src http://ppa.launchpad.net/bzr-beta-ppa/ubuntu intrepid main #Bazaar BETA

Blueman

deb http://ppa.launchpad.net/blueman/ppa/ubuntu intrepid main #Blueman
deb-src http://ppa.launchpad.net/blueman/ppa/ubuntu intrepid main #Blueman

blueyed (TV-Browser)

deb http://ppa.launchpad.net/blueyed/ppa/ubuntu intrepid main #blueyed (TV Browser)
deb-src http://ppa.launchpad.net/blueyed/ppa/ubuntu intrepid main #blueyed (TV Browser)

c-korn (wine, vlc)

deb http://ppa.launchpad.net/c-korn/ubuntu intrepid main restricted multiverse universe #wine, vlc

Conduit

deb http://ppa.launchpad.net/conduit/ubuntu intrepid main
deb-src http://ppa.launchpad.net/conduit/ubuntu intrepid main

Deluge

deb http://ppa.launchpad.net/deluge-team/ubuntu intrepid main #Deluge
deb-src http://ppa.launchpad.net/deluge-team/ubuntu intrepid main #Deluge

Gnome Do

deb http://ppa.launchpad.net/do-core/ubuntu intrepid main #Gnome Do
deb-src http://ppa.launchpad.net/do-core/ubuntu intrepid main #Gnome Do

Gnome Do BETA

deb http://ppa.launchpad.net/do-testers/ppa/ubuntu intrepid main #Gnome Do BETA
deb-src http://ppa.launchpad.net/do-testers/ppa/ubuntu intrepid main #Gnome Do BETA

Gnome Terminator

deb http://ppa.launchpad.net/gnome-terminator/ppa/ubuntu intrepid main restricted universe multiverse #Terminator
deb-src http://ppa.launchpad.net/gnome-terminator/ppa/ubuntu intrepid main restricted universe multiverse #Terminator

GnuCash

deb http://ppa.launchpad.net/gnucash/ppa/ubuntu intrepid main #GnuCash
deb-src http://ppa.launchpad.net/gnucash/ppa/ubuntu intrepid main #GnuCash

Hamster Applet

deb http://ppa.launchpad.net/hamster.support/ubuntu hardy main
deb-src http://ppa.launchpad.net/hamster.support/ubuntu hardy main

hyperair (Pidgin)

deb http://ppa.launchpad.net/hyperair/ubuntu intrepid main #hyperair (Pidgin)
deb-src http://ppa.launchpad.net/hyperair/ubuntu intrepid main #hyperair (Pidgin)

james-w (Ubuntu Netbook Remix)

deb http://ppa.launchpad.net/james-w/ubuntu intrepid main
deb-src http://ppa.launchpad.net/james-w/ubuntu intrepid main

mishd (Hotwire, PasswordSafe)

deb http://ppa.launchpad.net/mishd/ubuntu hardy main
deb-src http://ppa.launchpad.net/mishd/ubuntu hardy main

mozillateam (Mozilla Alpha)

deb http://ppa.launchpad.net/mozillateam/ppa/ubuntu intrepid main #Mozilla Alpha
deb-src http://ppa.launchpad.net/mozillateam/ppa/ubuntu intrepid main #Mozilla Alpha

Netbook Remix (official)

deb http://ppa.launchpad.net/netbook-remix-team/ppa/ubuntu intrepid main #Netbook-Remix
deb-src http://ppa.launchpad.net/netbook-remix-team/ppa/ubuntu intrepid main #Netbook-Remix

nijel (gammu)

deb http://ppa.launchpad.net/nijel/ubuntu intrepid main #gammu
deb-src http://ppa.launchpad.net/nijel/ubuntu intrepid main #gammu

OpenOffice.org

deb http://ppa.launchpad.net/openoffice-pkgs/ubuntu intrepid main #OpenOffice.org

stemp (Midori Browser)

deb http://ppa.launchpad.net/stemp/ubuntu intrepid main #Midori
deb-src http://ppa.launchpad.net/stemp/ubuntu intrepid main #Midori

SynCE

deb http://ppa.launchpad.net/synce/ubuntu intrepid main #SynCE
deb-src http://ppa.launchpad.net/synce/ubuntu intrepid main #SynCE

tualatrix (Ubuntu Tweak)

deb http://ppa.launchpad.net/tualatrix/ubuntu intrepid main #Ubuntu Tweak
deb-src http://ppa.launchpad.net/tualatrix/ubuntu intrepid main #Ubuntu Tweak

webkit-team (Midori)

deb http://ppa.launchpad.net/webkit-team/ppa/ubuntu intrepid main #Webkit-Team
deb-src http://ppa.launchpad.net/webkit-team/ppa/ubuntu intrepid main #Webkit-Team

Medibuntu 8.10

## Medibuntu - Ubuntu 8.10 "intrepid ibex"
## Please report any bugs on https://bugs.launchpad.net/medibuntu/
deb http://packages.medibuntu.org/ intrepid free non-free #Medibuntu
deb-src http://packages.medibuntu.org/ intrepid free non-free #Medibuntu

Opera

deb http://deb.opera.com/opera/ stable non-free #Opera

playdeb (Games)

deb mirror://www.getdeb.net/playdeb-mirror/hardy/// hardy/

Skype

Contents

deb http://download.skype.com/linux/repos/debian/ stable non-free #Skype

VirtualBox

deb http://download.virtualbox.org/virtualbox/debian intrepid non-free #VirtualBox

wine

## Bleeding edge wine repository for Hardy
## only uncomment it if you need it
deb http://wine.budgetdedicated.com/apt intrepid main #Wine bleeding edge
deb-src http://wine.budgetdedicated.com/apt intrepid main #Wine bleeding edge