There are monitors and there are monitors. What are the target applications? Remember that the video consumes a lot of computer resources and you should use a compatible video card which is not going to overload the system.
HDMI or DVI interface is found only on the high end monitors and (I am sorry to say) it is difficult for me to visually distinguish the final result.
If you are in high end multimedia or gaming, go for a good video card and monitor. If you are in routine computations and/or occasional designer, stick with the regular vga. They have been around for a long time.