Alright, I'll post this here since it seems a more appropriate place for a "bug fix" than the OT.
For anyone having problems with the dead zone of the Wired Xbox 360 Controller for Windows, such as I: The problem being fixed is anyone who has issues with the game switching from Running (or Sprinting) to Walking when pushing the left analog stick straight up, 12 o'clock.
After a million death's in Sen's Fortress because the character decided to randomly start walking while trying to get past the swinging blades I decided to Google the shit out of some forums looking for a fix. I soon came to realize that many people were having the EXACT same issue with the PC port of Devil May Cry 4 and several years ago some people figured out a third-party fix to that problem, so I thought "Fuck it, I bet it works for Dark Souls, too". Lo and behold, it does.
It requires a third-party program called x360ce, which is meant to emulate 360 controller functionality on a non-360 controller, but it also happens to fix this "wtf" bug. You can download the program from
http://code.google.com/p/x360ce/.
1. Extract the zip file directly into the Dark Souls directory that contains DATA.EXE.
2. Open the extracted EXE. Select Yes to each prompt asking to create a new file.
3. Allow it to download the Dark Souls profile from the internet.
4. Under the Controller 1 -> General tab, at the very bottom where it says 'Presets' choose "Controller (Xbox 360 Wireless Receiver for Windows)" then press 'Load' and then 'Save'.