It seems to me that there are two distinct camps here and this is only my interpretation of the previous three pages. There's the group who have bought a very expensive lens (50L) and are justifying it's merits (there are many but not with sharpness) with viggor and there are those who have the 50mm f1.4, a vastly cheaper model and they are generally more aggressive in their arguments and think that most 50L owners are crazy fools who buy kit because they like the red ring.
I have to say that I have owned two 50mm f1.4 lenses. One broke after a few years, it literally fell apart and the other I sold when i bought my 50L. The 50L is a vastly superior product. It feels a lot nicer to use, the AF ring feels quality and it's more usable and refined. The sharpness for an L lens is very disappointing and I nearly sent my copy back to the shop because I was shocked at how weak it was compared to my other primes. But it does have more contrast, wide open the files need minimal post processing. The flare is a lot less too. But it's so much more robust in it's construction. I've had mine for 5 years and it's never missed a beat...but it's not a lens I'd call "sharp". It's a reliable workhorse, but not Canon's finest.
I would never criticize a photographer for their choice in kit, it's a personal decision based around cost and features. No two people need the same kit. But I wonder if there is a bit of gear envy which goes on with this lens choice.
I just wish Canon would hurry up and make a better 50L, one which we can all be proud of. I think a 50mm f1.8 IS would be a great idea too.