I completed an upgrade to my main PC last week, and subsequently reinstalled my WinXP/Ubuntu dual boot. All went painlessly I am happy to report.
A specific issue during my configuration of Ubuntu, I had trouble enabling the 'Big Desktop' mode in the ATI CCC driver control panel. Each time I would apply my desired settings, they would be reverted to 'Clone' monitor output when I restarted. Being new to ATI, I figured it was a user error, but then I noticed that when I logged in as root, the settings worked fine, as it did in the Gnome login manager. Only in my own user account did the display revert to clone mode.
Some research on this issue revealed that the setting which forced clone monitor mode had been set in the configuration files for my Gnome user account, during or immediately after the OS installation. I found this link, which describes the processes I used to solve this issue, clear the Gnome configurations, and allow them to be resaved fresh with my desired configuration.
How to Reset Ubuntu/Gnome Settings to Defaults without Re-installing Linux FUD
Specifically, logging in as root and deleting the directories .gnome .gnome2 .gconf .gconfd .metacity was what solved my issue. A cautionary note, this was a minutes old install, there were no files I was afraid of losing.
That was my biggest hurdle, and it was easily enough cleared, which left me to enjoy the new hardware.
