Actually, they're really not the same thing. While the panels themselves can sometimes be identical, Eizos also have internal hardware color calibration (as in, independent from the graphics card), whereas the PA series NECs lack this and would be calibrated to an ICC profile linked to the graphics card.
This a lot of what makes Eizos so expensive, actually. But I would still wholeheartedly recommend an NEC. They're easily the best looking displays for the money.
To the OP:
Color correction makes a big difference with just about any published media, actually, whether it's for web, TV or film. It will give your work a professional edge. iMacs use very decent IPS-based panels so they're actually of reasonably good quality, minus the whole glossy factor.
Also understand that color correction for digital photos (typically sRGB color space) and broadcast video (usually NTSC/PAL or REC-709 color space) are inherently different. Computer monitors are by nature RGB devices, whereas televisions are YUV devices. For this reason, what looks correct on an RGB display won't on a YUV display, and vice-versa. This is definitely something to consider if you distribute work via broadcast or DVD/Blu-ray.
Many pro video editors and practically all post houses use calibrated NTSC broadcast monitors (connected via a capture or I/O interface) in conjunction with their normal computer display(s) to properly grade video. Matrox also makes a device called the MXO, which acts as scan converter, allowing you to use a quality computer monitor as a NTSC broadcast monitor.
But of course if, your primary delivery method will be Internet, a properly calibrated RGB monitor would likely work fine.