The Ultrasharp U-series are ( i believe ) all rated at 97-98% of adobe RGB color gamut. Basically, these are the type of monitors you have to have if you work in graphic design or photogrpahy/video. If you don't know that is, you don't need it.
That's debatable. We aren't still using EGA or VGA monitors. We aren't still using CRT.
The small sRGB space is likely going to be replaced by AdobeRGB in the future, especially since GB-LED backlights have been developed that support it.
The human eye can see a lot more than even AdobeRGB, so it's really time for content makers (like game studios) to move on. Besides, the other thing that was standing in the way of wide-gamut display adoption has been removed. That was poor support for sRGB. Recent panels have effective sRGB emulation modes.