First suggestion...check out a law school bookstore. They'll have all this stuff. Second suggestion if you can't do that...check out Barrister Books.
1. Hornbooks - books that explain aspects of the law in more detail. I wouldn't suggest buying any unless you really need them. Your library should have them.
2. Canned Briefs (apparently you can buy a book of them?) - a book of briefs (case summaries) for a particular casebook. If you get these, make sure you get the one keyed to your casebook. Also know that it's best to use these to supplement your own briefing, rather than replacing your own briefing. They might help you get an overall picture of a holding, but your prof. might want to focus on other things not covered.
3. Commercial Outlines - outline of the material/black letter law in an area. Again, generally keyed to a casebook.
4. Primers - dunno...hornbook?
5. Nutshells - "XXX in a Nutshell". It's a small book that explains black letter law in more detail. Haven't used them much, so can't say much about them.
E&E are Examples and Explainations - they're to help you get the basics of an area of law, relying on analysis using the black letter law. I like them as supplements.
Not the same as an outline which is more for organizing the material.
So, if you want to start reading about stuff early, the E&E's aren't bad for that. I'd hold off on other stuff until you find out what books you're going to have. Also, your professor might recommend stuff OR tell you that you don't need anything. If they say the latter, ask 2Ls/3Ls what you really need.