I have both Getting started Knitting Socks (FANTASTIC) and SKS, which I like very much, but for a beginner I would recommend Getting Started as more beginner friendly, with *very* clear instructions.
I also have 25 Favorite Socks, and I agree with RHRachel-it is wonderful, full of beautiful socks, almost every one of which I want to knit.
If you're at all interested in doing Magic Loop, 2-At-A-Time socks by Melissa Morgan-Oakes is also highly recommended. And yes, I have that one too
and only have 1.25 pairs of socks under my belt
But a girl can't have too many reference books, right? LOL.
have fun deciding!