99% of the time, modern day rotors don't really warp. The term "warp" is a misnomer. What really happens is when you use oem pads and run your brakes really hard the pads cannot disipate the heat quickly enough. This causes the pads to "breakdown" and permanately deposit some of the pad material onto the rotor. The pad material does not deposit evenly though and that is why you get the vibration or pulsing from your brakes. The simple way to fix this is to have your rotors turned. This will scrape the deposited pad material off of your rotor and give you smooth braking once again.

This common condition has symptoms just like a true "warped" rotor would have. Also, the fix is the same for both conditions so it doesn't really matter if you call them warped or not. I just thought you might like to know what is really going on.