A coworker and I were having a discussion about Gnome vs. KDE. I don't bring much to the conversation except my general observations: I want to prefer Gnome... but KDE just seems to be so much more cooked. After using the latest versions of both desktops in Mandrake Linux 9.0, it's pretty obvious to me that KDE is much more mature. When I can finally switch to Linux, I'll probably end up using KDE as the "base" with mostly Gnome-based apps like Galeon and Nautilus because the widgets in KDE seem a lot more user-friendly and refined.
But still, the K on all the KDE apps annoys me to no end. It's like the K on that car "Kompressor"... it's just freakin' weird... I have no such preconceived notions about the letter G, so the reverse is fine with me. (In fact, since Super Grover had a G on his chest, I might have an early-brainwashed affection for the letter. Grover is called "Coco" in Spain... all the Sesame Street characters have different names here and Big Bird doesn't exist! Can you believe it? I'm digressing, aren't I?)
Anyways, along these lines, I think I still am going to do all my user interfaces for GUI apps in the most generic form possible. So even though QT and GTK both have a bunch of bindings for whatever language you want to use - Python, for example - I'm still thinking XUL is the coming revolution in GUI development. I haven't WORKED with it yet, but I USE it every day (via Mozilla) and I'm sold on the whole concept of XML description for UI. And it's so rockin' to use the exact same UI on Linux as on Windows... for most people that's a pain, but for a wannabe switcher like me it's perfect.
We'll have to see how XUL acceptance progresses in the Java world. I think for a generation of developers who've been frustrated and disappointed with Swing dev, it's perfect. I haven't looked into it very deeply, but it would be awesome if there were some easy-to-use Java bindings. It would be sort of like another version of IBMs SWT - a cross platform way for Java to call local libraries for the GUI.
Later... Oooh! I almost forgot to add my other thought about Linux GUI. I'm hoping now that MacOSX has shown us a way to integrate *nix based app with a cool GUI, that maybe the Linux guys can start copying some of that OSes features. If you take a look at the new versions of KDE and Gnome, they're both basic clones of Windows... geeky clones, but clones. My main focus is the task-bar vs. the Dock, actually. I think the Dock seems quite useful and combined with the Apple Menu, it's a really nice way to keep track of running programs and favorites. Hopefully the next rev of the open GUIs will get a little inspiration from the Mac.