Third-Party Software Sources: Check All?

[zeerover]

To upgrade to the Firefox 3 RC1 without waiting for Ubuntu, I recently added a new third-party software source in System->Administration->SoftwareSources: ThirdPartySoftware, as per the advice in this helpful post (http://ubuntuforums.org/showthread.php?p=5011212#post5011212). While in that tab, I noticed four Third-PartySoftware sources already there, only one of which was checked:

1. http://archive.canonical.com/ubuntu hardy partner
2. http://archive.canonical.com/ubuntu hardy partner (Source Code)
*3. http://packages.medibuntu.org/ hardy free non-free
4. http://packages.medibuntu.org/ hardy free non-gree (Source Code)

The * beside 3. represents the only checked item. I have two questions:

1. Should I check any or all of these unchecked items?
2. Are there other sources I should add?

Thanks!
Isaac

[Pumalite]

Updates and backports

[Vadi]

Feel free to enable the partner repository.

As for the source code ones, I wouldn't recommend it - unless you're wanting to download the source code of the programs to see what they're made of / modify it. In case you'd like to do that sometime later, you'll know where to look :)