Well, the idea was that if the original account you were using was corrupt somewhere, creating a new one would make the problem disappear. That would be without manipulating anything, just logging in and moving forward without the problem.
So, I guess you're saying that after logging in under the new account, you still had the problem. However, every User Account does have its own Desktop plist file. If you didn't find it, you weren't looking in the right place.
The next thing to try would be to download the 10.6.3 Combo Updater from the Apple site's Downloads page. Install that over your existing OS and see if it cleans things up.