While xresprobe and ddcprobe work with the video card and monitor I'm using, simplifying desktop installation, the default VESA mode of 1024x768 is shifted a few pixels offscreen to the right. I can remedy this by pressing the autoresize on the monitor but, since it doesn't store this value, I need to do it every time I resume from a power saving mode.

In order to fix this I need to modify the X server configuration with the following steps.

Shutdown gdm, and log into a terminal as root. Run "startx". Then, from inside the x session, run "xvidtune". Then click "left" a few times, then "apply". Do this until the display is properly centered and click "show". This dumps a modeline to stdout:

"1024x768"     78.80   1024 1056 1152 1312    768  769  772  800 +hsync +vsync

Save this information and edit /etc/X11/xorg.conf (assuming you're using the xorg server). I tend to prefer to covert it into the "Mode" syntax as it's slightly more readable.

Section "Monitor"
        Identifier      "AX3819"
        Option          "DPMS"
        HorizSync       30-60
        VertRefresh     50-75
        Mode "1024x768"
                DotClock        78.80
                HTimings        1024 1056 1152 1312
                VTimings        768  769  772  800
                Flags           "+HSync" "+VSync"
        EndMode
EndSection

Exit from your root X session, restart gdm, et viola. (Obviously, if you've modified the X config you can't currently rely on it being automatically updated via dpkg configuration. It's a shame the X config is monolithic and not broken up a la the current Exim4 packaging.)