So for Christmas my old man gets me a Porter Cable random orbital buffer, which was awesome. Then he tells me to order what I need for it, and the first thing that pops into my head is "Griot's Garage", but I want to get your advice first...

What should I be buying to use with my Porter Cable? I am thinking Clay Bar (not for use with PC of course, but I need it) polish, wax, and sealer, but what brand?

Well first thing is get some cheap stuff and practice on a cheap car, scrap fender etc, something besides your car.

I have not tried a PC before but my buddy who does detailing one time tried to teach me how to buff my car with his buffer. Now it wasnt a random orbital so maybe they are easier to handle than what he uses, but it wanted to rip itself out of my hands....

This is what he uses... http://www.dewalt.com/us/products/tool_detail.asp?productID=174

Edit: Whoops missed some stuff

Get a claybar any will do a decent job, just make sure you keep it lubed up.

As far as the product goes I think griots is overpriced for what it is....

I'll probably end up practicing on the 4runner or the Jeep. Both are scratch/dent cars, so if I mess up a little it won't be the end of the world, but thanks for the reply.

Meh, Griots Garage tends to be overpriced. FWIW I typically order my detailing supplies from http://www.topoftheline.com They are usually the least expensive, and don't screw you on shipping.
Their clay isn't my favorite though, so just get Clay Magic at Autozone.
If you order from Top of the line, you need
PC backing plate
Foam pads (probably two orange, two white and a finishing pad)
Polish (I'd recommend Optimum polish, and maybe the compound)
Klasse AIO is a great chemical polish/cleaner <- Outstanding base for whatever wax/sealant you want to use.
How much are you looking to spend? Grape tire dressing is phenomenal! So is their tire cleaner and APC... I could recommend *lots* of stuff from that site :)

Other good detailing supply places are
http://www.danase.com
http://www.exceldetail.com <- Good Microfiber towels and waffle weave drying towels

I'm sure you've visited http://www.autopia.org ? It's a good place to start, lots of articles on how to clay, polish etc...