Question : Formatting hard drive on a Mac

Hello.

So I bought a MacBook Pro (Intel 2.8, 4gb ram, etc.) from this guy. He had a bunch of software and other stuff in it which I don't need so I simply deleted all of it.The computer works great but sometimes I get the "colored circle" and it seems to get stuck.  

 I've already put all my stuff in the computer but I always wondered if it would have been a good idea to format the drive and reinstall the system to make it "as new" again before I start using it. I have a few questions:

1.  Would it do any good to the hard drive to format it and reinstall the system? Would you advice I do that?
2.  To format the drive do I simply reinstall the OS (10.6 that is) or is there a step prior to reinstall the system?
3. I already have a bunch of my stuff in the computer (applications, music, pictures, documents, Firefox (saved passwords, booksmarks, etc.)  How do I back up all of this so that I don't loose it upon formatting the hard drive and how would I install back to the new formatted drive?

Thank you for your help!

Answer : Formatting hard drive on a Mac

Is this what you mean?  http://www.washington.edu/doit/Brochures/Academics/cprep.html

Or have you already been accepted, and are just trying to get ready to leave for college in the fall?
(like this maybe?  http://www.collegeview.com/dorm_room_supply.html )