For debugging problems with installed apps, it would be nice if one could install the -dbg packages and automatically get the source code installed as well. This makes it much easier to analyze backtraces in the debugger (you can see function calls in their context, maybe with source code comments etc.).

I have seen this on RHEL 5, where I could debug (and, as result, work around) a Firefox freeze: after installing the existing -debuginfo packages, the source code was installed somewhere on disk, and gdb automatically picked it up (and so did kdbg then). It took maybe 10 minutes to get this working, where most of the time was spent looking for the -debuginfo repository.

In contrast, I suppose the only way to get source code for debugging under Ubuntu is to build the packages again on the local machine, with some "debug" flag thrown in somewhere. This is really annoying and time-consuming (all in all, the process probably takes ~ 1 hour), and usually discourages me from starting actual debugging.

Using a fresh Karmic Beta installation and a cheap USB DVB-T receiver (WinTV NovaT-Stick SE), there was no guidance to actually get a TV picture on screen.
Interesting thing is, the underlying software appears to be ready but the user interface is lacking. I think here's an easy way to give users a great "just works" experience - the foundations are all there.

(Disclaimer: I bought this DVB-T stick after checking that there's a Linux driver available - with other hardware there might be driver problems that make installation much harder. This idea is meant for the "hardware works but software doesn't" cases)

Currently, in Ubuntu one can use shipit to request a CD. DVD's would be much better than CD as they can/have more data in it.