Buy it online and pick up when you get there. In my past experience, they are different lines. Buying a pre-sale ticket will get you into a faster moving line. All they need to do is check your printout, and give you a wristband or stamp.
Even better is to buy your presale, then do advance pickup during the week before the con if you live/work downtown or have a friend who does. I work right on Bay/Front, so I'm picking up the wristbands for all my friends on Tuesday the week of the con and none of us will have to line up at all.
Not sure if advance pickup is for full weekend passes only though. I always get the full pass.
Costume Con - Kili in a dress
Atomic Lollipop - Come visit me at the Make-Your-Own-Button free craft booth!
Polar Chill - check out my costume DIY panel and workshop
FanExpo - Iron Man Mark VII version 2, Pacific Rim Jaeger pilot?
FanExpo - fem!Iron Man Mark VII - The Iron Man Armor Project
Atomic Lollipop - Vanellope von Schweetz; raver!Sailor Mars