Madhusudan Singh <spammers-go-here@spam.invalid> writes:

> Did a bunch of updates on my Debian Etch system. Among others, KDE was
> upgraded to 3.5. Now, when X starts up (tried both kdm and gdm), there is a
> strange kind of translucency present - the mouse cursor is invisible, and
> the text is visible,

Check if something like this is present in your /etc/X11/xorg.conf:
Section "Extensions"
Option "Composite" "Enable"
EndSection

If so, put a # in front of "Option".
--
Regards
Jes Vestervang