the only real reason to have a 120hz monitor is for gaming or 3d or a combination of both. the problem is that all 120hz monitors are tn type panels which are the lowest quality panel you can get.
personally i feel that stepping up to a better panel type is a much better option then getting a better refresh rate which personally i can not say i notice a huge difference. i can notice a difference between a tn panel and something nicer though.
the choice is yours... you have to decide if you want to go with a quality panel with better viewing angles or if a fast refresh rate matters most to you. note that you arent going to "be better" at games because of a panel type so its only just your own preferences.