Not yet.... Still at 60Hz... but I don't game much on the PC (even though I have a Huge Steam games backlog!!! LOL)

This is my main monitor --> http://www.newegg.com/Product/Product.aspx?Item=N82E16824001553

Not sure why I went with a 27 incher... probably overcompensating for other things... let's just leave it at that...

Hans, what monitor is that 7970 driving?

I haven't heard of any 120hz monitors that large.  I have a 23 inch 120hz that I game on.  I have a 24 inch IPS right next to it, and you do lose slight color quality and viewing angle.  That said, I won't go back to 60hz for gaming or video, the difference in framerate is fantastic. 

None yet. Most of the 120hz (and occasional 144hz) monitors are of 1080 variety, from 23-27 inches. The lot of them are TN panels with all that entails, except for the rare Catleap Rev 2B IPS that can be overclocked that high. 2560x1440 res, but most cap at around 90-100hz to the best of my knowledge.

With 120hz monitors and NVIDIA Lightboost, there's a hack to increase fluidity and motion sharpness by taking advantage of strobing backlights. This is akin to a CRT and as such flicker fatigue may result from such usage.

You can do something very similar, vendor-agnostic, with certain Samsung 120hz monitors.