Recent versions of the xorg-server bring about many improvements, among them, particularly, a complete cooperation with HAL to autoconfigure input devices and displays. That's mainly a good thing, but there are, as always, also problems with this new implementation.
For example, experienced Debian or Ubuntu users were dumbfounded when trying to set the resolution of their display via 'dpkg-reconfigure xserver-xorg' in a reasonably up-to-date version of their OS. This option just doesn't exist anymore. ;)
If you live on the bleeding edge, it's perfectly normal that the proprietary graphics driver declares to be not compatible with the shining, new xorg-server you've just updated to. Entirely your fault, freak! :D Well, at least for Nvidia users there's an easy way out:
Option "ignoreABI" "True"
Add that to the "ServerFlags" section of your xorg.conf, and you're done (well, at least there is some hope *g*)
Other symptoms of living on the edge are not as easy to fix, such as the strange inability of some applications such as VMware and Warsow to properly recognize the codes for certain keys, such as the arrows. Finding a solution for VMware proved to be easy, but for Warsow, there's only a workaround called w-a-s-d ;) This will certainly boost my mediocre FPS performance to levels which I never dreamed of reaching ... *g*
To add something useful: here's how one can check the codes for certain keys, if they don't work in your host system (such as, e.g., a volume key on a notebook). You can then add the keycodes to your personal ~/.Xmodmap.
xev | grep -A2 --line-buffered '^KeyRelease' \ | sed -n '/keycode /s/^.*keycode \([0-9]*\).* (.*, \(.*\)).*$/\1 \2/p'
Note that this won't help if the problem is restricted to a specific application such as VMware as described above.