DVI can make a huge difference, yes, since its a Digital signal.
If both your monitor and video card supports it, go for it
"However, when connected via a digital connection, often labeled DVI (for Digital Visual Interface), no digital-to-analog conversion is required, and there should be no loss or corruption of the signal. As a result, when running at its native resolution, an LCD should give you a cleaner and crisper image than you'd see on a CRT. "
I hope this helps.