Pawn structure books Which book is better for a 1700-1800 player? 


Pawn Power in Chess by Hans Kmoch (originally Die Kunst der Bauernführung, 1956)
Pawn Structure Chess by Andrew Soltis
Chess Structures: A Grandmaster Guide by Mauricio Flores Rios, or 
The Power Of Pawns by Jörg Hickl.
I would take a look at The Art of the Middle Game by Keres and Kotov. It is the only book I know of which devotes serious attention to pawn structure in a way that goes beyond opening development.

If you liked My System you might also check out Chess Praxis (also by Nimzowitch). It isn't on pawn structure specifically, but details Nimzowitch's theory of Prophylaxis, covering pawn structure in the process of doing so. It's a good follow up to My System.

As to the books in your question I've heard great things about Pawn Power in Chess, but haven't read it myself so can only report second hand.