Computersloeber :
The difference is that 120 and 144 Hz monitors support a high framerate output by your GPU. So say your GPU produces 80FPS you will be able to see all of the frames on a 120 or 144Hz (Hz means images per second) monitor. But on a 60Hz monitor you would waste 20 frames because the refresh rate of the monitor is too slow to show them. Now i think with a Gtx 760ti you don't need an 120 or 144 Hz monitor, because that card just isn't powerfull enough to get a high framerate on most games. I would only buy a 120 or 144Hz monitor if you have powerfull hardware, but thats just my opinion.
This is a big misconception most people have with refresh rates and FPS. If you are rendering more FPS than your refresh rate, the monitor still shows all of them, it's just that you only end up seeing part of each. 120 FPS on a 60hz monitor, will display all 120 frames per second, but you'll only see half of each frame displayed on average, with a tear between them (the change from 1 frame to the next causes the two images to not line up which looks like a tear).
As mentioned before, one of the best things about a 120+hz monitor is it reduces how noticeable tearing is. I forgot how bad tearing was with a 60hz monitor until I started playing DA: Inquisition after a driver update that ended up setting my hz back to 60 without me realizing. Once I started playing, it was very distracting until I realized what the cause was and I switched it back to 120hz.
If you use V-sync, then you end up with a FPS cap at your refresh rate, so your GPU will only be able to generate 60 FPS if you have a 60hz monitor, and 120 FPS with a 120hz monitor. As far as 120hz versus 144hz, that is mostly just a matter of the old versus the new monitors. All the new high refresh monitors are doing 144hz now. The older models are 120hz. 144hz is better, but barely. Most people won't notice a difference, and if you use ULMB or Lightboost for low persistence and motion blur, 120hz is the highest you can go anyways.