Re: artifacts, screen unreadable after exiting X
Happens all the time. Try adding
Option "ConnectedMonitor" "CRT"
Option "IgnoreDisplayDevices" "TV"
to your XF86Config file. The second line will probably disable the TV-Out, so if you need that you may want to disable the framebuffer rather than using these options. To do that, just remove any "vga=" options from your GRUB or LILO configuration and reboot. Then the consoles will be 640x480 with no graphics support, but they work.
Unfortunately, neither fix seems to work for people using DVI cables to hook up the monitor. I use a flat panel monitor but with a standard VGA cable and both fixes work for me. I do not use the TV-Out but have noticed that I had problems on the cards I have tried with three outputs, but not the one I tried with only two.