I bought a Samsung SyncMaster 204B monitor. It’s a 1600×1200 20” with a 5 ms response and bright colors (for a complete review of it, you can point your browser to HardwareCentral). Here I just want to let you know it shines perfectly with Kubuntu :) and that here you can find my xorg.conf, which is a modified version of the one I use with my laptop (Acer TravelMate 8003Lmi which is shipped with ATI Mobility Radeon 9700). I switch between the two xorg.conf of my laptop inside or outside my office (aka with or without the Samsung monitor).
UPDATE (2006-12-21): if it still does not work, try following this Wiki then activate the driver directly with the Kubuntu video control manager (and use one of the ATI versions of my xorg.conf).
UPDATE (2007-04-23): with Feisty it works even better. :)
[...] Pro). Surprisingly, Hardy choosed the correct resolution at the first attempt! How simpler in comparison to an older Kubuntu! The Samsung SyncMaster 245B with Kubuntu by Carlo Perassi, unless otherwise [...]