When I was asked in the past what linux desktop lacks I kept on telling that we need a way to have a more common look and feel among several desktop environments. Opening a gtk/gnome-app shouldn't look weird in kde, same thing with opening a qt/kde-app in gnome. Dialogs for files, printing etc. should look common. You can discuss hours if the button-order should be »Ok«/»Cancel« or »Cancel«/»Ok«, but it's definitely the worst if this changes from app to app.

Today I found this little tool called KGtk, which (partly) does what I want. It's a wrapper around gtk-apps to call the kde file open dialog. It also contains the same thing for qt apps (that don't use kdelibs).
Using it is quite trivial, just start
kgtk-wrapper.sh [somegtkapp]
or
kqt-wrapper.sh [someqtapp]

I really like it, because there are some gtk-apps I don't want to miss (especially gimp), but I think the new gtk fileselector is really a sin of usability.

While this is (cited from webpage) »a quick-and-dirty LD_PRELOAD hack«, it imho shows exactly how it should work. The freedesktop.org standardisation is a very good thing, but it has to go much further. We need something like »app tells DE to open a file-open dialog« instead of »app opens it's file dialog«. We need the same thing for printing, iconsets, button-order and probably much more.