The 700 generation is the newest. Along with newer technologies,its slightly more powerful.
An Nvidia cards name has three parts(as of now,it's subject to change in the future)
The first numeral is the Generation,i.e 500,600 and 700.
The second numeral is a representation of its performance level.i.e 750 is a "Consumer"(or entry level) card,the 760 is an Enthusiast level card,the 770 is a performance and the 780's are extreme.
The third part is usually a modification or revision indicator, I.E the 750 Ti is a revised 750,and slightly stronger because of it.
TL;DR the 760 is the new 660.