I recently built a PC with an Intel DZ77BH-55K motherboard. I was hoping to avoid some graphics issues by using the built-in Intel HD Graphics. Unfortunately, although there are no show-stopping driver issues with this board, the default configuration in Kubuntu 12.04 (and others) isn't right.
The problem is, I was using the HDMI output, and the resolution on my monitor was fine until kdm started. After inspection, I noticed that the video driver seems to think there is a VGA1 connected, despite the fact that the motherboard has no VGA output. As a result, the 1024x768 VGA1 output was used as the default, and the HDMI output was a clone of it (at 1024x768). This can be fixed by disabling VGA1 and setting HDMI2 to the right resolution, but it's on a per session basis.
I did find a way to semi-permanently fix it through a xorg.conf file. If you want to generate one yourself, switch to a virtual terminal (Ctrl+Alt+F1) and run "sudo service kdm stop" (or gdm or whatever). And then run "sudo X -configure". You can modify the new ~/xorg.conf.new to your needs.
I removed everything except the HDMI output. Here is the result. If you're using HDMI on a DZ77BH-55K board, you can probably just drop this into /etc/X11/xorg.conf, reboot, and you shouldn't have any problems on a fresh install (if you've messed with the settings in KDE already, just remove "~/.kde/share/config/startupconfig" first.