Installed Karmic with ext4 on a new PC today. Installed FGLRX afterwards. All of a sudden the PC froze completely. No mouse-movement, no keyboard. Hard reset. After reboot lots of configuration files that were recently changed had zero length. The system became unusable due to this (lots of error messages in dpkg etc). Installed again on ext3. No problems ever since. I wonder why this is installed by default as Ubuntu is supposed to be a user-friendly distro. Is it really necessary to squeeze out the last bit of extra performance for the sake of data security? This is certainly not desired for a desktop system. At least an explicit warning that this could happen should appear during installation.