After staring at my increasingly annoying defective 24" Samsung (broken) CCFL, I've replaced it and my 19" inch Fujitsu Siemens TFT by 2 IIyama 24" LED monitors and hooked up my old 17" Acer al1714 for kicks as well.
The monitors work, but Ubuntu seems to have trouble remembering what screen is where after rebooting.
Update 9-8: It saves the configuration, just not before logging in.
I also hookup up a keyboard with multimedia keys (i.e. volume keys). They don't seem to work out of the box in Ubuntu 14.04.
Apparently it is a bug after upgrading to Ubuntu 14.04. I installed dconf-tools, started dconf-editor and looked up org.gnome.settings-daemon.plugins.media-keys. Here I found volume-up and volume-down and reset them to XF86AudioRaiseVolume, etc. Now it works.