MS in computer science specialisation selection

Hello everyone!
i m in my research phase, and while goin thru the various university websites, i have observed that each and every MS program in computer science has da following research areas:
Artificial intelligence, Computational Biology, Computer Architecture, Database systems, Graphics, Programming languages, robotics, scientific computing, security, systems and networking, theory of computing.

first question: while shortlisting the universities , is it necessary to choose and keep a research area in mind? like shud i use univ X becoz i like security and it is a research area available in Univ. X?:confused::confused:

Second question: Hw can i found out wat research areas wud be more favorable keeping future job search in mind in US? Hw can i get more information!:confused:

Buddies dis confounded soul really needs help, as i m trying for FALL 2013! so kindly help me understand dis!

Cheerz!