Well, I followed up: I got KDE up and running on my Debian box and worked through some small QT programs. (As an aside, compiling KDE from sources really sucks and takes forever on my 500MHz Celeron. I should have expended the effort and found packaged binaries.) The upshot: some things I like a lot about KDE, but overall I prefer GNOME. (KNode, however, is about the best newsreader I have come across and handles binaries much better than Pan does.)
That said, I do find programming in QT to be pretty pleasant. I'm still not too fond of the signal/slot weirdness, but it works, and once you get the conceptual picture of what it does, it's pretty straightforward.
As I was fooling around on my box, I also tried several MPEG-viewers. Xine seems to be the best one going, but even it had lots of hiccups and crashed a lot. Video is one area where Linux *really* falls down. (Not surprising since so much video technology is hidden behind patents.) I do expect Xine to get much better over time.