It seems (for me anyway) that if you select the option at the end of the Xconfigurator session to start X automagically upon bootup that as soon as you enter your login and password it re-loads X and you have to login one more time. This only happens upon first bootup (ie not when you just logout and back in again), and doesn't seem to affect Root, only normal users. (?) I'm pretty new at this, so I may have missed something important.
I only had this problem when X was already configured to start automatically (I re-ran Xconfigurator a month after initial install to set up X for a different monitor...)
we can't duplicate this problem, and have no other reports of similar difficulties, so we must assume it is user configuration error.