Okay, Batch Reply to a bunch of posts:
noobmonkey[27]:
If you got the so-called "sexy" pointer (:P) then plasma (the desktop shell) probably crashed. In my experience this virtually never happens anymore, so it could just be a quirk of your system. If you feel like trying it again (you can install the kubuntu-desktop package ontop of Ubuntu - it's just a different spin, not a different OS), and reporting a bug with useful info, I'm sure KDE would appreciate it. Also be aware that hitting Alt+F2 and typing in "plasma-desktop[enter]" should restart it manually, and then you can see if it was just temporary thing.
go1dfish[28]:
Without getting into an argument, the developers do consider it "user-ready" at this point, and for the most part I'd agree, however that view admittedly sounds a bit weak in light of noobmonkey's post. :P At this point I'd say it's the usual quesion of "who is it ready for?" rather than "is it ready?" (cf. "Year of the Linux Desktop" debate -grin-)

noobmonkey[38]:
Great! As I think I mentioned, though, Ubuntu is shipping an old beta of KDevelop4, so it lacks some fairly important features (working debugging being one, if I remember correctly). That said, even if you can't wait for it to be released and packaged for Ubuntu, it's still makes an awesome code editor, and I'd fully recommend it if it works for you.
As for your comments about DEBs, you might want to read up on it. You can essentially think about packages as being an archive file (like a ZIP or tarball) with a file tree of binaries and what-have-you, and some metadata. In reality they're more complicated, and often horribly pedantic, but that's the gist. So, while you can technically just dump your compiled program into your filesystem and run it, the proper way is to package it into a package for your distro (Maemo uses DEBian packages because of its Debian heritage). This is a reasonably time-consuming process to learn and to do right, so when you're just messing around, you probably don't want to worry about it. Just remember - files that aren't packaged aren't tracked by the system database, so if you leave them lying around and forget to clean them up, you may have issues - or at least cruft. If you do this, I'd recommend sticking them in /home/user/bin (which you'd have to create).

noobmonkey[45]: X has to run on a logical display. DISPLAY is an environment variable that is set when you fire up an X session (e.g. login). Since you're not logged into your graphical session as root (I hope not, anyway!), you need to set it manually.

Oh, and to put in my two cents about the C++/Python discussion, I would note that not only is C++ much nicer than C, but Qt takes care of most of the remaining messy bits. Python is still probably easier for many things, but it's a matter of preference as well as the situation, really. Also note that (probably) the majority of Linux software can be used directly by C++ programs, but there aren't Python bindings for everything (although it's close!).