As you say, there are lots of books on the subject (and I have quite a few of them).
The thing to remember is that they all contain the same information so they will all get you through a College class (but it's worth asking your tutor for a recommendation).
Buying your own is a matter of choice dictated by prose style, approach and cost.
Approach is probably the biggy. Different books look at different aspect so you get a slightly different view (as well as some different pictures and photographers).
A good one to start with covering most things well is
Photography by Ian Jeffrey (
http://www.thamesandhudson.com/books/Photography/9780500201879.mxs/27/0/ ). Thames & Hudson actually do a cracking good selection of books and they are all worth a browse.
Another good one (but I think it is out of print) is
The Birth of Photography by Brian Coe (one time curator of the Kodak Museum).
I have one or two others I like to use in conjunction with these - in particular a French history which gives you a whole new view on the subject and introduces you to lots of great photographers you've never heard of.
The bottom line is: haunt second hand bookshops and buy all the HoP books you can afford. They will all be useful
