I've encountered some bugs with the Ubuntu software center and the browser on Ubuntu touch. I'm not sure if I should submit them to the official repo, since I'm talking about apps, not core OS elements.
Where should these bugs be reported?
If the programs come from the official repositories, then yes, you submit bug reports to launchpad.net. In the case of packages in the universe pocket, they generally receive less attention and so may not be fixed by someone in the Ubuntu world, but hopefully someone ( and you yourself could jump in and do this ) will forward the bug to the upstream developers, who are more likely to fix it. It is helpful when doing this to make sure that the bug still applies to the latest upstream version first, but testing this does require that you build the upstream program from source yourself and test it.