how to properly break in a new car

ive heard two distinctly different and opposite theories for the break in process one is run it hard (lots of full throttle accelerations basically driving like you stole it) for only a short time (couple hundred miles) and the other the more conventional run it easy, never go more then 1/4 throttle dont pass 3000rpm for about 1000km what's common to both methods is never staying at a constant speed/gear/or throttle position, letting it rev up and down so that the internals (piston rings, bearings, etc.) to seal properly i was just wondering which method most of you guys use i'm probably going to go for the more conventional method, no full throttle accelerations for first 1000 or so kms