Version:           4.8.0 (using KDE 4.8.0) 
OS:                Linux

On KDE 4.6.x and at least on the initial versions of KDE 4.7 (I migrated to Gnome for some time so I didn't use KDE 4.7 for its whole lifecycle), when you had a multi-monitor setup you should configure it on System Settings->Display and Monitor and click to save the current setting as default, so on the next login KDE would loading your setup. But this isn't working anymore on KDE 4.8, on the next login I would have a ugly low-resolution image setted on both screens (and using clone-mode instead of one screen beside another).

Reproducible: Always

Steps to Reproduce:
Just add a monitor to make a multi-monitor setup. Go to System Settings->Display and Monitor, configure your multi-monitor setup, click "Save as default", logout and login again.

Actual Results:  
You will have the default behavior for multi-monitor screens, clone-mode+low-resolution screen on both monitors.

Expected Results:  
The setup you made on Display and Monitors to be preserved on every login.

I have a Samsung R480 notebook, which have a NVIDIA GeForce 310M GPU. I am currently using nouveau drivers (including the experimental 3D Mesa drivers) on a fleshly installed version of Arch Linux (just finalized the instalation). Installed the full kde-meta package. Tested on both VGA and HDMI outputs of my notebook, neither do work.