If it's of any help, I install TDE selectively and don't have 
kgtk-qt3-trinity installed, I do have gtk-qt-engine-trinity. Almost all 
gtk stuff works fine here (except zenity radiolist)

I use also xfce but find TDE (especially with Slavek's patches) 
preferable for everyday use and stable enough.

Whatever is causing login failures, Segfault xsetroot, dcopserver... for 
my package setup at least there are no such problems.

David