You haven't specified what release of Fedora you're running (F8 or F9) although I suspect F9, nor what updates were made before the change.
The whole X11/Xorg mess is still under heavy development and revision, with changes occuring constantly. A regression is really not a surprise. Most importantly, is direct rendering still working ? Check with:
Result will be either "Yes" or "No". Personally, I don't understand why 1024x768 isn't good enough, but I suppose if you're used to 1440x900... Please attach copy of Xorg.0.log in full. It appears that there are problems because xorg.conf specifies LCD but that snippet from Xorg.0.log says CRT....