I would say that a wide-gamut display is NOT really necessary if you only intend to publish to the web. As you know, sRGB is pretty much the lowest common denominator for presentation on the web. Unless you expect the majority of your viewers to be using color-managed web browsers capable of properly rendering images tagged with AdobeRGB, there aren't really any merits to getting a wide-gamut display for such purposes.

The need for wider gamut displays relegated more to those who expect maximum quality from their prints, particularly those who print with their own equipment, and for printing equipment that supports the bulk of the AdobeRGB gamut. Top of the line consumer grade and most of the recent commercial grade ink jet printers from Epson, Canon, and some off-brand Giclee-grade printers support wide gamuts, and the envelope is constantly being pushed. AdobeRGB is certainly a possibility, and with some of the latest advancements in Epson inks, I believe they can print an even larger fully-encompassing gamut on a couple types of papers. If you don't expect such high-caliber prints on a regular basis, then I would say a wide-gamut (98% AdobeRGB) or ultra-wide-gamut display (120%+ AdobeRGB) are really unnecessary.