Are you going to a Part 147 school? As others have mentioned, you'll never get a better deal on Snap-On, Mac, or Matco then you will now. I believe Craftsman does some deals for A&P students as well.
I've got mostly Snap-On tools. Are they the best? Yes and no. In many ways Mac and Matco are on par. One thing that I have noticed in my years of turning wrenches is that they have the best return policy. Things like wrenches should hardly ever have to be replaced, but e-z outs are something that wear with use, and the Snap-On guys always replaced them without blinking an eye, while the Mac guy would only replace it if broke.
Craftsman is a decent way to get started. Harbor freight is ok for somethings, very few things, dead-blows, scrapers, sealant tools, etc. come to mind. Once in awhile they have S&K brand wrenches there which are alright. Most of the tools at HF are junk in my opinion, especially when used in difficult applications. I've seen many HF wrenches sprung and rendered useless.
Once you're working in the field, a good piece of advice handed down to me was if you need to borrow a tool three times, you need to buy it. Most mechanics understand that a new guy is going to show up for his first job with limited tools, and are willing to lend a tool. But the third time you're seeking to borrow a particular tool should tell you something!
And as far as the admonition to not purchase 6 point sockets, I don't understand that. 98% of the time the 6 point is the correct choice. It is sturdier that a twelve point and provides greater grip strength. Twelve point is good for certain nuts and s acceptable in low torque applications.
