zonealarm can cause this. no standard solution for the problem. if you have it, just live with it.
if you dont have zonealarm, i dont think its the unwanted startup programs as INS-ANI said, as you said it takes you time to get to the logon screen itself. all startup progs run AFTER the welcome screen. so you might have some drivers loading before that, check any unwanted drivers you might have installed. or maybe any boot-time optimizations you might have done like boot time defragmentation, registry compact, system file checking, something like that maybe?