Top dog for gaming monitors right now is Benq xl2420t.
btw dont get taken in with the marketing too much, in reality it wont be 2ms and it doesnt matter as long as it stays under 8ms (if youre running 120hz).
also if you really want it for 120hz make sure you got a good graphics card that can use it in games because spending that money so your desktop is smooth isnt worth it.
if you dont have the power to run your games consistently above 60fps I would suggest checking out an ips monitor that has below 16ms. the dell ultrasharp u2312hm looks great.