Whether or not the image QUALITY will be better depends on what kind of monitor you get. If you have a TN panel now and you get another TN panel, then the visual quality is probably not going to be much different if it is the same resolution and refresh rate.
If you get a unit that has a higher resolution (Which is going to increase the demand on your graphics card, so you will likely see fewer FPS than with a lower resolution) then things are going to LOOK a lot better in some cases. If you get one with a higher refresh rate you will have a SMOOTHER image while gaming, but again, you are going to need to be able to provide somewhere near the same FPS as your refresh rate or you will be likely to see an increase in tearing.
For a GTX...