There was a power outage at my house during the early morning hours of Halloween. My computer was off and I had to turn on my computer again. At the KDE login screen, my keyboard and mouse failed to work.
I went through an interactive bootup and chose not to load kdm, taking me to a regular console, and my keyboard worked just fine. I tried looking for solutions (and missed the correct solution, which I'll get to later), did not find one that worked, and decided to reinstall Gentoo.
I decided to go with a 64 bit installation this time, but still ran across the issue of my keyboard and mouse failing. Finally, I find that Xorg started to use HAL. Putting the line
Option "AutoAddDevices" "false"
in the ServerFlags section of xorg.conf fixed this.
Now to find out how to get my dual monitor setup to work like it did in my old machine, despite using the same xorg.conf (minus the line added above) from my old setup.