I read a review of Canon's 135mm f/2.0 lens last week, and it looks like a spectacular lens. As you might imagine, it's a really large chunk of glass, and the sample images in the review look fantastic, but one of the things that struck me was the crazy cost difference between equipment like this versus the stuff many of us use -- are you really going to get photos that are ten times better using equipment that costs ten times as much?
The part of the review that really jumped out at me were the shots on page 4 where Jason looked at the bokeh of this lens. A couple months ago, I posted a photo that highlighted some of the bokeh characteristics of my 50mm f/1.8 lens. As you might recall, in the shot I looked at, the background was nicely out of focus, but the lights from the Christmas tree took on a really distinct pentagonal shape that I wasn't crazy about. Compare this to the bokeh in the first photo on page 4, which shows that creamy smooth bokeh that gets people drooling, but when stopped down to f/3.2, it starts showing a shaped bokeh, too (though it's a nicer octagonal shape).
So is that "L" lens better than the 50mm f/1.8? Undoubtedly. Is it $1000 better? I'd say that largely depends on whether you know how to take advantage of its strengths. Unless you've been shooting for a while, there's a good chance that you'll do almost as well with a more affordable lens. When you know why you need the big-buck lens, go for it, but in the meantime, make sure you're getting the most out of the equipment you've got.