Yeh, go for the sony... think about it, the display is pretty much all of the output of the computer, and you'll be able to use the same monitor when you next upgrade your PC. A decent monitor with a nice high refresh rate will do your eyes a lot of good. I found the quality of my gaming improved significantly once I upgraded from a crappy 15" Hitachi to a Sweeeet Sony 19 incher. Furthermore, Sony just plain rock and you should give them lots of money.
-Loïc