With the new xrandr functionality - we should be able to kick some serious hot-plugging backside with monitors; indeed 'xrandr' seems to be pretty cool:

[ start ]:
michael@t60p:~/Desktop> xrandr
Screen 0: minimum 320 x 200, current 1600 x 1200, maximum 1600 x 1600
VGA_1 disconnected
PANEL connected 1600x1200+0+0 304mm x 228mm
   1600x1200      60.0*+   60.0  
DVI-D_1 disconnected
  1024x768_60 (0x51)   64.1MHz
        h: width  1024 start 1080 end 1184 total 1344 skew    0 clock   47.7KHz
        v: height  768 start  769 end  772 total  795           clock   60.0Hz

[ hot plug monitor ]:

michael@t60p:~/Desktop> xrandr
Screen 0: minimum 320 x 200, current 1600 x 1200, maximum 1600 x 1600
VGA_1 connected
   1280x1024      60.0 +   59.9     60.0  
   1024x768       60.0     60.0     58.8  
   800x600        60.3     60.0     58.7  
   640x480        60.0  
PANEL connected 1600x1200+0+0 304mm x 228mm
   1600x1200      60.0*+   60.0  
DVI-D_1 disconnected
  1024x768_60 (0x51)   64.1MHz
        h: width  1024 start 1080 end 1184 total 1344 skew    0 clock   47.7KHz
        v: height  768 start  769 end  772 total  795           clock   60.0Hz

Unfortunately, the gnome display properties systray applet appears to be worse than useless & now shows ~next to nothing useful [ either before or after ]. I would expect it to -at-least- tell me my current resolution (1600x1200) & refresh rate - even if it cannot be changed. I'd also expect it to allow me to select an external monitor resolution too.

Or at least do something more ;-)