vncserver: выбор среды KDE или GNOME

#cat ./.vnc/xstartup

#!/bin/sh

# Uncomment the following two lines for normal desktop:
# unset SESSION_MANAGER
# exec /etc/X11/xinit/xinitrc

[ -x /etc/vnc/xstartup ] && exec /etc/vnc/xstartup
[ -r $HOME/.Xresources ] && xrdb $HOME/.Xresources
xsetroot -solid grey
vncconfig -iconic &
xterm -geometry 80x24+10+10 -ls -title "$VNCDESKTOP Desktop" &
# twm &
enlightenment &

Улавливаешь? ;-)) Меняешь 
enlightenment & 
на
startkde &

Или вот так -
#cat ./.vnc/xstartup

#!/bin/sh

# Red Hat Linux VNC session startup script
unset SESSION_MANAGER
exec /etc/X11/xinit/xinitrc

где в /etc/X11/xinit/xinitrc

if [ -f $HOME/.Xclients ]; then
        exec $DBUS_LAUNCH $HOME/.Xclients || \
        exec $HOME/.Xclients
elif [ -f /etc/X11/xinit/Xclients ]; then
        exec $DBUS_LAUNCH /etc/X11/xinit/Xclients || \
        exec /etc/X11/xinit/Xclients
else
       # failsafe settings.  Although we should never get here
       # (we provide fallbacks in Xclients as well) it can't hurt.
       xclock -geometry 100x100-5+5 &
       xterm -geometry 80x50-50+150 &

       if [ -x /usr/X11R6/bin/twm ]; then
               exec /usr/X11R6/bin/twm
       fi
fi

и далее -  /etc/X11/xinit/Xclients

GSESSION="$(which gnome-session 2>/dev/null)"
STARTKDE="$(which startkde 2>/dev/null)"

# check to see if the user has a preferred desktop
PREFERRED=
if [ -f /etc/sysconfig/desktop ]; then
    . /etc/sysconfig/desktop
    if [ "$DESKTOP" = "GNOME" ]; then
        PREFERRED="$GSESSION"
    elif [ "$DESKTOP" = "KDE" ]; then
        PREFERRED="$STARTKDE"
    fi
fi
....  
и так далее...

а в - /etc/sysconfig/desktop

DESKTOP="KDE"

Вообще, читай больше манов и системныз скриптов..