How do I wipe my MBP drive to default? My MacBook Pro fell and is kinda cracked so since I have warranty from BestBuy, I want to do a complete wipe of the HDD and essentially restore it like it was brand new before I return it. (They’ll probably do it too, but I want to do it myself just to be sure.)

I’ve backed up all my data and all I need to do is wipe it.

What is the best way to go about this? I want to erase but obviously leave it in a working manner with OS on it etc.

I thought I found the answer here, but that’s for an older OS and the MBA machine.

I’m running the latest update of Mountain Lion.
What you should do is similar in concept to the answer that you've quoted. The main difference is that your MBP will have the Restore partition on its drive instead of the USB solution for the MBA. 

Follow the instructions on Apple's recovery partition page:


  Just hold down Command-R during startup and OS X Recovery springs into
  action. It lets you choose from common utilities: You can run Disk
  Utility to check or repair your hard drive, erase your hard drive and
  reinstall a fresh copy of OS X, or restore your Mac from a Time
  Machine backup.


Since you've already backed up your data, pick the erase and reinstall option, and you'll have a clean copy of OS X installed on the MBP before you bring the machine back for servicing/replacement.