it's really up to you. i have a cheap 17" CRT monitor (15.5" viewable). although i am used to the monitor, i always want to buy the vx922 listed above so i can run at higher resolutions and not go blind. (as far as desktop work goes)
i've seen a monitor like the one you have, and i can guarantee that the difference between it and the vx922 would be noticeable.
another thing that makes me want to switch is because my monitor is so cheap that in games such as fear some lighting is projected through my screen like a strobe light (literally)... it really takes away from the experience in my opinion, because it really isn't pleasurable. with an lcd, you don't have this effect.